Solid-state imaging device and electronic device for enhanced color reproducibility of images

ABSTRACT

A solid-state imaging device according to an embodiment includes: a semiconductor substrate including a photoelectric conversion element; a lens disposed above a first light incident surface of the photoelectric conversion element; and a plurality of columnar structures disposed on a surface parallel to the first light incident surface that is located between a second light incident surface of the lens and the first light incident surface of the photoelectric conversion element. The columnar structure includes at least one of silicon, germanium, gallium phosphide, aluminum oxide, cerium oxide, hafnium oxide, indium oxide, tin oxide, niobium pentoxide, magnesium oxide, tantalum pentoxide, titanium pentoxide, titanium oxide, tungsten oxide, yttrium oxide, zinc oxide, zirconia, cerium fluoride, gadolinium fluoride, lanthanum fluoride, and neodymium fluoride.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Phase of International PatentApplication No. PCT/JP2018/047397 filed on Dec. 21, 2018, which claimspriority benefit of U.S. Patent Application No. 62/609,839 filed in theU.S. Patent Office on Dec. 22, 2017. Each of the above-referencedapplications is hereby incorporated herein by reference in its entirety.

FIELD

The present disclosure relates to a solid-state imaging device and anelectronic device.

BACKGROUND

Conventionally, in electronic devices having an imaging function such asdigital still cameras and digital video cameras, for example,solid-state imaging elements such as charge coupled device (CCD) andcomplementary metal oxide semiconductor (CMOS) image sensors are used.

For example, light entering a CMOS image sensor is photoelectricallyconverted by a photodiode as a photoelectric conversion element in apixel. Charges generated by the photodiode are transferred to a floatingdiffusion layer through a transfer transistor, and converted into avoltage. The voltage is applied to the gate of an amplifier transistor.As a result, a pixel signal of voltage level corresponding to thecharges accumulated in the floating diffusion layer appears at the drainof the amplifier transistor.

CITATION LIST Patent Literature

Patent Literature 1: Japanese Laid-open Patent Publication No.2009-238942

SUMMARY Technical Problem

In conventional solid-state imaging elements, a color filter thatselectively transmits light having a particular wavelength is disposedon each pixel in order to acquire color images and infrared images(hereinafter referred to as “IR images”). However, for example, in aregion where the image height is high, light obliquely enters pixels,and hence there is a possibility that light that has been transmittedthrough a color filter in a pixel enters an adjacent pixel (leaks).There is another possibility that light that has been transmittedthrough the color filter is reflected by wiring inside the element toenter an adjacent pixel. When the entering (leakage) of light to anadjacent pixel as described above occurs, colors are mixed among pixels,and as a result, there is a problem in that color reproducibility ofimages acquired by the image sensor decreases.

In view of the above, the present disclosure proposes a solid-stateimaging device and an electronic device capable of improving colorreproducibility.

Solution to Problem

For solving the problem described above, a solid-state imaging deviceaccording to one aspect of the present disclosure has a semiconductorsubstrate including a photoelectric conversion element, a lens disposedabove a first light incident surface of the photoelectric conversionelement, and a plurality of columnar structures disposed on a surfaceparallel to the first light incident surface that is located between asecond light incident surface of the lens and the first light incidentsurface of the photoelectric conversion element, wherein the columnarstructure includes at least one of silicon, germanium, galliumphosphide, aluminum oxide, cerium oxide, hafnium oxide, indium oxide,tin oxide, niobium pentoxide, magnesium oxide, tantalum pentoxide,titanium pentoxide, titanium oxide, tungsten oxide, yttrium oxide, zincoxide, zirconia, cerium fluoride, gadolinium fluoride, lanthanumfluoride, and neodymium fluoride.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional diagram illustrating a cross-sectionalstructure example of an image sensor employed for a structured lightsystem.

FIG. 2 is a block diagram illustrating a schematic configuration exampleof an electronic device having a solid-state imaging device according toa first embodiment mounted thereon.

FIG. 3 is a block diagram illustrating a schematic configuration exampleof a CMOS image sensor according to the first embodiment.

FIG. 4 is a circuit diagram illustrating a schematic configurationexample of a unit pixel according to the first embodiment.

FIG. 5 is a diagram illustrating a layout example of color filtersaccording to the first embodiment.

FIG. 6 is a diagram illustrating a stacked structure example of the CMOSimage sensor according to the first embodiment.

FIG. 7 is a cross-sectional diagram illustrating a cross-sectionalstructure example of the CMOS image sensor according to the firstembodiment.

FIG. 8 is a schematic diagram illustrating positions at which pillarsaccording to the first embodiment are formed.

FIG. 9 is a layout diagram illustrating an arrangement example of thepillars according to the first embodiment.

FIG. 10 is a layout diagram illustrating another arrangement example ofthe pillars according to the first embodiment.

FIG. 11 is a diagram for explaining a wavelength selection function of apillar array according to the first embodiment.

FIG. 12 is a diagram illustrating an example of a light transmissionspectrum that can be implemented by the pillar array according to thefirst embodiment.

FIG. 13 is a diagram illustrating an example of a relation between thediameter of the pillar and the wavelength of light absorbedby/transmitted through the pillar array according to the firstembodiment.

FIG. 14 is a diagram illustrating a manufacturing method for the pillarsaccording to the first embodiment (No. 1).

FIG. 15 is a diagram illustrating the manufacturing method for thepillars according to the first embodiment (No. 2).

FIG. 16 is a diagram illustrating the manufacturing method for thepillars according to the first embodiment (No. 3).

FIG. 17 is a diagram illustrating the manufacturing method for thepillars according to the first embodiment (No. 4).

FIG. 18 is a diagram illustrating the manufacturing method for thepillars according to the first embodiment (No. 5).

FIG. 19 is a diagram illustrating the manufacturing method for thepillars according to the first embodiment (No. 6).

FIG. 20 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to a secondembodiment.

FIG. 21 is a layout diagram illustrating an arrangement example ofpillars according to the second embodiment.

FIG. 22 is a cross-sectional diagram illustrating a shape example ofpillars according to a third embodiment.

FIG. 23 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to a fourthembodiment.

FIG. 24 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to a fifthembodiment.

FIG. 25 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to a sixthembodiment.

FIG. 26 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to a seventhembodiment.

FIG. 27 is a layout diagram illustrating an arrangement example of apillar array, according to the seventh embodiment, that transmits lighthaving a wavelength component of red.

FIG. 28 is a layout diagram illustrating an arrangement example of apillar array, according to the seventh embodiment, that transmits lighthaving a wavelength component of green.

FIG. 29 is a layout diagram illustrating an arrangement example of apillar array, according to the seventh embodiment, that transmits lighthaving a wavelength component of blue.

FIG. 30 is a diagram illustrating an example of a light transmissionspectrum when a pillar array configured by pillars having differentdiameters is combined with the color filter, according to the seventhembodiment, that selectively transmits light having a wavelengthcomponent of red (No. 1).

FIG. 31 is a diagram illustrating an example of a light transmissionspectrum when a pillar array configured by pillars having differentdiameters is combined with the color filter, according to the seventhembodiment, that selectively transmits light having a wavelengthcomponent of red (No. 2).

FIG. 32 is a diagram illustrating a layout example of color filtersaccording to an eighth embodiment.

FIG. 33 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to the eighthembodiment.

FIG. 34 is a diagram for explaining spectroscopic characteristics ofcombined filters according to the eighth embodiment.

FIG. 35 is a layout diagram illustrating an arrangement example ofpillars for each unit pixel according to the eighth embodiment.

FIG. 36 is a cross-sectional diagram illustrating a configurationexample of a pillar array, according to the eighth embodiment, thatselectively transmits light having a wavelength component of green.

FIG. 37 is a diagram for explaining spectroscopic characteristics ofcombined filters according to a ninth embodiment.

FIG. 38 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to the ninthembodiment.

FIG. 39 is a diagram illustrating a plan layout example of pillarsaccording to the ninth embodiment.

FIG. 40 is a diagram for explaining spectroscopic characteristics ofcombined filters according to a tenth embodiment.

FIG. 41 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to the tenthembodiment.

FIG. 42 is a diagram illustrating a plan layout example of pillarsaccording to the tenth embodiment.

FIG. 43 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to an eleventhembodiment.

FIG. 44 is a diagram illustrating a plan layout example of pillarsaccording to the eleventh embodiment.

FIG. 45 is a diagram for explaining spectroscopic characteristics ofcombined filters according to the eleventh embodiment.

FIG. 46 is a plan diagram illustrating a layout example of a pixel arrayaccording to a twelfth embodiment.

FIG. 47 is a diagram illustrating a plan layout of unit patternbelonging to a center region in FIG. 46.

FIG. 48 is a cross-sectional diagram illustrating a cross-sectionalstructure of a surface A-A in FIG. 47.

FIG. 49 is a cross-sectional diagram illustrating a cross-sectionalstructure of a surface B-B in FIG. 47.

FIG. 50 is a diagram illustrating a plan layout of unit patternsbelonging to a peripheral region in FIG. 46.

FIG. 51 is a cross-sectional diagram illustrating a cross-sectionalstructure of a surface C-C in FIG. 50.

FIG. 52 is a cross-sectional diagram illustrating a cross-sectionalstructure of a surface D-D in FIG. 50.

FIG. 53 is a plan diagram illustrating a layout example of a pixel arrayaccording to a thirteenth embodiment.

FIG. 54 is a diagram illustrating a plan layout of unit patternsbelonging to an intermediate region in FIG. 53.

FIG. 55 is a cross-sectional diagram illustrating a cross-sectionalstructure of a surface E-E in FIG. 54.

FIG. 56 is a cross-sectional diagram illustrating a cross-sectionalstructure of a surface F-F in FIG. 54.

FIG. 57 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to a fourteenthembodiment.

FIG. 58 is a diagram illustrating a plan layout example of pillarsaccording to the fourteenth embodiment.

FIG. 59 is a diagram illustrating an example of spectroscopiccharacteristics of a pillar array provided in a unit pixel according tothe fourteenth embodiment.

FIG. 60 is a diagram for explaining propagation of light that hasobliquely entered a peripheral part of a color filter according to thefourteenth embodiment.

FIG. 61 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to a fifteenthembodiment.

FIG. 62 is a diagram illustrating a plan layout example of pillarsaccording to the fifteenth embodiment.

FIG. 63 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to a sixteenthembodiment.

FIG. 64 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to a seventeenthembodiment.

FIG. 65 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to an eighteenthembodiment.

FIG. 66 is a diagram illustrating a plan layout example of color filtersand photodiodes according to the eighteenth embodiment.

FIG. 67 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a general CMOS image sensor.

FIG. 68 is a diagram illustrating a plan layout example of aphotoreceiver chip according to a nineteenth embodiment.

FIG. 69 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to the nineteenthembodiment.

FIG. 70 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to a twentiethembodiment.

FIG. 71 is a diagram for explaining spectroscopic characteristics of apillar array according to the twentieth embodiment.

FIG. 72 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to a twenty-firstembodiment.

FIG. 73 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to a twenty-secondembodiment.

FIG. 74 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to a twenty-thirdembodiment.

FIG. 75 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a shielding film in a CMOS image sensor accordingto a twenty-fourth embodiment.

FIG. 76 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to a twenty-fifthembodiment.

FIG. 77 is a diagram illustrating a manufacturing method for an on-chiplens according to the twenty-fifth embodiment (No. 1).

FIG. 78 is a diagram illustrating the manufacturing method for anon-chip lens according to the twenty-fifth embodiment (No. 2).

FIG. 79 is a diagram illustrating the manufacturing method for theon-chip lens according to the twenty-fifth embodiment (No. 3).

FIG. 80 is a diagram illustrating the manufacturing method for theon-chip lens according to the twenty-fifth embodiment (No. 4).

FIG. 81 is a diagram illustrating the manufacturing method for theon-chip lens according to the twenty-fifth embodiment (No. 5).

FIG. 82 is a diagram illustrating the manufacturing method for theon-chip lens according to the twenty-fifth embodiment (No. 6).

FIG. 83 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to a twenty-sixthembodiment.

FIG. 84 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to a twenty-seventhembodiment.

FIG. 85 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to a twenty-eighthembodiment.

FIG. 86 is a block diagram illustrating an example of a schematicconfiguration of a vehicle control system.

FIG. 87 is an explanatory diagram illustrating an example ofinstallation positions of an outside-vehicle information detection unitand imaging units.

DESCRIPTION OF EMBODIMENTS

Referring to the drawings, embodiments of the present disclosure aredescribed in detail below. In the following embodiments, the sameportions are denoted by the same reference symbols to omit overlappingdescriptions.

The present disclosure is described in the order of the following items:

1. First Embodiment

1.1 Configuration example of electronic device

1.2 Configuration example of solid-state imaging device

1.3 Configuration example of unit pixel

1.4 Basic function example of unit pixel

1.5 Layout example of color filters

1.6 Stacked structure example of solid-state imaging device

1.7 Cross-sectional structure example of unit pixel

1.8 Shape of pillars

1.9 Arrangement of pillars

1.10 Wavelength selection function by pillars

1.11 Pillar array in first embodiment

1.12 Position of pillar array

1.13 Material of pillars

1.14 Diameter and pitch of pillars

1.15 Manufacturing method for pillars

1.16 Actions and effects

2. Second Embodiment

3. Third Embodiment

4. Fourth Embodiment

5. Fifth Embodiment

6. Sixth Embodiment

7. Seventh Embodiment

8. Eighth Embodiment

8.1 Layout example of color filters

8.2 Cross-sectional structure example of unit pixel

8.3 Spectroscopic characteristics of combined filters

8.4 Actions and effects

9. Ninth Embodiment

9.1 Spectroscopic characteristics of combined filters

9.2 Cross-sectional structure example of unit pixel

9.3 Plan layout example of pillars

9.4 Diameter and pitch of pillars

9.5 Actions and effects

10. Tenth Embodiment

11. Eleventh Embodiment

12. Twelfth Embodiment

12.1 Layout of pixel array

12.2 Center region

12.2.1 Layout of unit pattern

12.2.2 Cross-sectional structure of unit pixel

12.3 Peripheral region

12.3.1 Layout of unit pattern

12.3.2 Cross-sectional structure of unit pixel

12.4 Spectroscopic characteristics of pillar array

12.5 Actions and effects

13. Thirteenth Embodiment

13.1 Intermediate region

13.1.1 Layout of unit pattern

13.1.2 Cross-sectional structure of unit pixel

13.2 Spectroscopic characteristics of pillar array

13.3 Actions and effects

14. Fourteenth Embodiment

14.1 Cross-sectional structure example of unit pixel

14.2 Plan layout example of pillars

14.3 Spectroscopic characteristics of pillar array

14.4 Function of pillar as optical waveguide

14.5 Actions and effects

15. Fifteenth Embodiment

16. Sixteenth Embodiment

17. Seventeenth Embodiment

18. Eighteenth Embodiment

19. Nineteenth Embodiment

19.1 Plan layout of photoreceiver chip

19.2 Cross-sectional structure example of shielding region

19.3 Diameter, pitch, and height of pillars

19.4 Actions and effects

20. Twentieth Embodiment

21. Twenty-First Embodiment

21.1 Cross-sectional structure example of shielding region

21.2 Actions and effects

22. Twenty-Second Embodiment

23. Twenty-Third Embodiment

24. Twenty-Fourth Embodiment

25. Twenty-Fifth Embodiment

25.1 Cross-sectional structure example of unit pixel

25.2 Manufacturing method for on-chip lens

25.3 Actions and effects

26. Twenty-Sixth Embodiment

27. Twenty-Seventh Embodiment

28. Twenty-Eighth Embodiment

29. Applications to mobile body

1. First Embodiment

First, a first embodiment is described in detail with reference to thedrawings.

For example, one cause of leakage of light transmitted through a colorfilter in a region where the image height is high to an adjacent pixelis a long distance from a light incident surface of the color filter toa light incident surface of a photoelectric conversion element.

For example, in image sensors that acquire images of light having aparticular wavelength outside a visible light region, such as infraredimages, in addition to color images, as exemplified by image sensorsemployed for a structured light system, a structure in which a pluralityof color filters are vertically stacked may be provided in order tosuppress the entering of light having a particular wavelength to pixelsthat acquire color images. In such a structure, however, the distancefrom a light incident surface of a color filter at the top to a lightincident surface of a photoelectric conversion element becomesredundant. As a result, there is a high possibility that light that hasobliquely entered leaks into an adjacent pixel.

As a specific example, an image sensor 900 that acquires an infraredimage (hereinafter referred to as “IR image”) by infrared light(hereinafter referred to as “IR light”) in addition to a color image ofthree primary colors of RGB as illustrated in FIG. 1 includes, as pixelsthat acquire a color image of three primary colors of RGB: a photodiodePD having a color filter 907R that transmits light having a wavelengthcomponent of red (R), the color filter 907R being disposed on the lightincident surface side; a photodiode PD having a color filter 907G thattransmits light having a wavelength component of green (G), the colorfilter 907G being disposed on the light incident surface side; and aphotodiode PD having a color filter 907B that transmits light having awavelength component of blue (B), the color filter 907B being disposedon the light incident surface side.

An IR filter 917IR that blocks IR light is provided between the colorfilters 907R, 907G, and 907B and the photodiodes PD. In other words, acolor filter in each of the pixels that acquire a color image of threeprimary colors of RGB has a structure in which the color filter 907R,907G, or 907B and the IR filter 917IR are stacked. In this manner, theincidence of IR light to the photodiodes PD in the pixels that acquire acolor image of three primary colors of RGB is reduced.

The image sensor 900 includes, as a pixel that acquires an IR image, aphotodiode PD having a color filter that selectively transmits IR light,the color filter being disposed on a light incident surface of thephotodiode PD. As illustrated in FIG. 1, for example, this color filter907IR that transmits IR light may have a structure in which a colorfilter 907R that transmits light having a wavelength component of red(R) and a color filter 907B that transmits light having a wavelengthcomponent of blue (B) are stacked.

As described above, when the color filter has the stacked structure, adistance from a light incident surface of a color filter located at thetop to the light incident surface of the photodiode PD increases(increase in height). Thus, the leakage of light L1 to L3 transmittedthrough the color filters to adjacent pixels becomes redundant. As aresult, there is a problem in that color reproducibility in acquiredimages decreases. The color reproducibility may be such that colors inreality are truly reproduced.

In view of the above, in the present embodiment, a solid-state imagingdevice and an electronic device in which columnar structures(hereinafter referred to as “pillar”) are used as an IR filter thatblocks IR light, so that the leakage of light to an adjacent pixel dueto the increased height can be suppressed while suppressing theincidence of IR light to pixels that acquire color images, are describedin detail by way of examples.

1.1 Configuration Example of Electronic Device

FIG. 2 is a block diagram illustrating a schematic configuration exampleof an electronic device having a solid-state imaging device according tothe first embodiment mounted thereon. As illustrated in FIG. 2, anelectronic device 1 includes, for example, an imaging lens 20, asolid-state imaging device 10, a storage 30, and a processor 40.

The imaging lens 20 is an example of an optical system that condensesincident light and forms an image of the light onto a light receivingsurface of the solid-state imaging device 10. The light receivingsurface may be a surface of the solid-state imaging device 10 on whichphotoelectric conversion elements are arranged. The solid-state imagingdevice 10 photoelectrically converts the incident light to generateimage data. The solid-state imaging device 10 executes predeterminedsignal processing, such as noise reduction and white balance adjustment,on the generated image data.

For example, the storage 30 is configured by a flash memory, a dynamicrandom access memory (DRAM), or a static random access memory (SRAM),and stores therein image data input from the solid-state imaging device10.

For example, the processor 40 is configured by using a centralprocessing unit (CPU), and may include an application processor thatexecutes an operating system and various kinds of application software,a graphics processing unit (GPU), and a baseband processor. Theprocessor 40 executes various kinds of processing as needed on imagedata input from the solid-state imaging device 10 and image data readfrom the storage 30, executes displaying of the image data to users, andtransmits the image data to the outside through a predetermined network.

1.2 Configuration Example of Solid-State Imaging Device

FIG. 3 is a block diagram illustrating a schematic configuration exampleof a complementary metal-oxide-semiconductor (CMOS) solid-state imagingdevice (hereinafter simply referred to as “CMOS image sensor”) accordingto the first embodiment. The CMOS image sensor is an image sensorproduced by applying or partially using a CMOS process. For example, aCMOS image sensor 10 according to the first embodiment is configured bya back-illuminated CMOS image sensor.

For example, the CMOS image sensor 10 according to the first embodimenthas a stacked structure in which a semiconductor chip in which a pixelarray 11 is formed and a semiconductor chip in which peripheral circuitsare formed are stacked. Examples of the peripheral circuits may includea row driver 12, a column processing circuit 13, a column driver 14, anda system controller 15.

The CMOS image sensor 10 further includes a signal processor 18 and adata storage 19. The signal processor 18 and the data storage 19 may beprovided in the same semiconductor chip as that of the peripheralcircuits, or may be provided in another semiconductor chip.

The pixel array 11 has a configuration in which unit pixels (hereinaftersometimes simply referred to as “pixels”) 50 having photoelectricconversion elements that generate and accumulate charges correspondingto the amount of received light are disposed in a two-dimensional gridpattern in a row direction and a column direction, that is, in a matrixpattern. The row direction is an arrangement direction of pixels in apixel row (horizontal direction in the figures), and the columndirection is an arrangement direction of pixels in a pixel column(vertical direction in the figures). The specific circuit configurationand details of the pixel structure of the unit pixel are describedlater.

In the pixel array 11, in the pixel arrangement of the matrix pattern, apixel driving line LD is wired along the row direction for each pixelrow, and a vertical signal line VSL is wired along the column directionfor each pixel column. The pixel driving line LD transmits a drivingsignal for driving pixels to read signals from the pixels. In FIG. 3,the pixel driving lines LD are illustrated as wiring one by one, but arenot limited to the one-by-one basis. One end of the pixel driving lineLD is connected to an output end of the row driver 12 corresponding toeach row.

The row driver 12 is configured by a shift register or an addressdecoder, and drives all the pixels in the pixel array 11 simultaneouslyor drives the pixels in units of rows. In other words, the row driver 12constitutes a driving unit that controls the operation of each pixel inthe pixel array 11 together with the system controller 15 that controlsthe row driver 12. The illustration of a specific configuration of therow driver 12 is omitted. In general, the row driver 12 includes twoscanning systems, that is, a reading scanning system and a sweepscanning system.

The reading scanning system sequentially and selectively scans unitpixels in the pixel array 11 in units of rows in order to read signalsfrom the unit pixels. The signal read from the unit pixel is an analogsignal. The sweep scanning system performs sweep scanning on a readingrow for which the reading scanning is to be performed by the readingscanning system, prior to the reading scanning by an exposure time.

Through the sweep scanning by the sweep scanning system, unnecessarycharges are swept from photoelectric conversion elements in unit pixelsin a reading row, and the photoelectric conversion elements are reset.By sweeping the unnecessary charges by the sweep scanning system(reset), what is called electronic shutter operation is performed. Theelectronic shutter operation refers to an operation for discardingcharges in a photoelectric conversion element and starting new exposure(starting accumulation of charges).

A signal read by the reading operation of the reading scanning systemcorresponds to the amount of light received after the previous readingoperation or electronic shutter operation. A period from a readingtiming by the previous reading operation or a sweep timing by theelectronic shutter operation to a reading timing by the current readingoperation is an accumulation period (also referred to as “exposureperiod”) of charges in a unit pixel.

Signals output from unit pixels in a pixel row selected and scanned bythe row driver 12 are input to the column processing circuit 13 throughthe vertical signal lines VSL for each pixel column. The columnprocessing circuit 13 performs, for each pixel column in the pixel array11, predetermined signal processing on signals output from pixels in aselected row through the vertical signal lines VSL, and temporarilystores therein pixel signals after the signal processing.

Specifically, the column processing circuit 13 performs, as the signalprocessing, at least noise reduction processing such as correlateddouble sampling (CDS) and double data sampling (DDS). For example, fixedpattern noise intrinsic to pixels, such as reset noise and thresholdfluctuation in amplifier transistors in pixels, is removed by the CDS.In addition, for example, the column processing circuit 13 has ananalog-digital (AD) conversion function, and converts an analog pixelsignal read from a photoelectric conversion element into a digitalsignal and outputs the digital signal.

The column driver 14 is configured by a shift register or an addressdecoder, and sequentially selects reading circuits (hereinafter referredto as “pixel circuits”) corresponding to a pixel column in the columnprocessing circuit 13. Through the selection scanning by the columndriver 14, pixel signals that have been subjected to signal processingfor each pixel circuit by the column processing circuit 13 aresequentially output.

The system controller 15 includes a timing generator that generatesvarious kinds of timing signals and other components. The systemcontroller 15 controls the driving of the row driver 12, the columnprocessing circuit 13, and the column driver 14 based on various kindsof timings generated by the timing generator.

The signal processor 18 has at least an arithmetic processing function,and performs various kinds of signal processing such as arithmeticprocessing on pixel signals output from the column processing circuit13. The data storage 19 temporarily stores therein data necessary forthe signal processing in the signal processor 18.

For example, image data output from the signal processor 18 may besubjected to predetermined processing by the processor 40 in theelectronic device 1 having the CMOS image sensor 10 mounted thereon, ortransmitted to the outside through a predetermined network.

1.3 Configuration Example of Unit Pixel

FIG. 4 is a circuit diagram illustrating a schematic configurationexample of a unit pixel according to the first embodiment. Asillustrated in FIG. 4, a unit pixel 50 includes a photodiode PD, atransfer transistor 51, a reset transistor 52, an amplifier transistor53, a selection transistor 54, and a floating diffusion layer FD.

The selection transistor 54 has the gate connected to a selectiontransistor driving line LD54 included in the pixel driving lines LD. Thereset transistor 52 has the gate connected to a reset transistor drivingline LD52 included in the pixel driving lines LD. The transfertransistor 51 has the gate connected to a transfer transistor drivingline LD51 included in the pixel driving lines LD. The amplifiertransistor 53 has the drain connected to, through the selectiontransistor 54, a vertical signal line VSL the one end of which isconnected to the column processing circuit 13.

In the following description, the reset transistor 52, the amplifiertransistor 53, and the selection transistor 54 are sometimescollectively referred to as “pixel circuit”. The pixel circuits mayinclude the floating diffusion layer FD and/or the transfer transistor51.

The photodiode PD photoelectrically converts incident light. Thetransfer transistor 51 transfers charges generated in the photodiode PD.The floating diffusion layer FD accumulates therein the chargestransferred by the transfer transistor 51. The amplifier transistor 53causes a pixel signal having a voltage value corresponding to thecharges accumulated in the floating diffusion layer FD to appear in thevertical signal line VSL. The reset transistor 52 discharges the chargesaccumulated in the floating diffusion layer FD. The selection transistor54 selects a unit pixel 50 that is a target to be read.

The photodiode PD has an anode grounded and a cathode connected to thesource of the transfer transistor 51. The transfer transistor 51 has thedrain connected to the source of the reset transistor 52 and the gate ofthe amplifier transistor 53. A node as a connection point thereofconstitutes the floating diffusion layer FD. The drain of the resettransistor 52 is connected to a vertical reset input line (not shown).

The source of the amplifier transistor 53 is connected to a verticalcurrent supply line (not shown). The drain of the amplifier transistor53 is connected to the source of the selection transistor 54. The drainof the selection transistor 54 is connected to the vertical signal lineVSL.

The floating diffusion layer FD converts the accumulated charges into avoltage having a voltage value corresponding to the amount of thecharges. For example, the floating diffusion layer FD may be thecapacitance to the ground. The floating diffusion layer FD is notlimited thereto, and may be a capacitance added by intentionallyconnecting a capacitor to a node at which the drain of the transfertransistor 51, the source of the reset transistor 52, and the gate ofthe amplifier transistor 53 are connected.

1.4 Basic Function Example of Unit Pixel

Next, the basic function of the unit pixel 50 is described withreference to FIG. 4. The reset transistor 52 controls discharging(resetting) the charges accumulated in the floating diffusion layer FDin accordance with a reset signal RST supplied from the row driver 12through the reset transistor driving line LD52. By turning on thetransfer transistor 51 when the reset transistor 52 is on, chargesaccumulated in the photodiode PD in addition to the charges accumulatedin the floating diffusion layer FD can be discharged (reset).

When a reset signal RST of High level is input to the gate of the resettransistor 52, the floating diffusion layer FD is clamped to a voltageapplied through the vertical reset input line. In this manner, thecharges accumulated in the floating diffusion layer FD are discharged(reset).

When a reset signal RST of Low level is input to the gate of the resettransistor 52, the floating diffusion layer FD is electricallydisconnected from the vertical reset input line, and becomes a floatingstate.

The photodiode PD photoelectrically converts incident light, andgenerates charges corresponding to the amount of the light. Thegenerated charges are accumulated on the cathode side of the photodiodePD. The transfer transistor 51 controls the transfer of charges from thephotodiode PD to the floating diffusion layer FD in accordance with atransfer control signal TRG supplied from the row driver 12 through thetransfer transistor driving line LD51.

For example, when a transfer control signal TRG of High level is inputto the gate of the transfer transistor 51, charges accumulated in thephotodiode PD are transferred to the floating diffusion layer FD. On theother hand, when a transfer control signal TRG of Low level is suppliedto the gate of the transfer transistor 51, the transfer of charges fromthe photodiode PD is stopped.

As described above, the floating diffusion layer FD has the function forconverting charges transferred from the photodiode PD through thetransfer transistor 51 into a voltage having a voltage valuecorresponding to the amount of the charges. Thus, in the floating statein which the reset transistor 52 is turned off, the potential of thefloating diffusion layer FD is modulated depending on the amount of theaccumulated charges.

The amplifier transistor 53 functions as an amplifier an input signalfor which is a potential fluctuation in the floating diffusion layer FDconnected to the gate thereof. An output voltage signal thereof appearsin the vertical signal line VSL through the selection transistor 54 as apixel signal.

The selection transistor 54 controls the appearance of the pixel signalin the vertical signal line VSL performed by the amplifier transistor 53in accordance with a selection control signal SEL supplied from the rowdriver 12 through the selection transistor driving line LD54. Forexample, when a selection control signal SEL of High level is input tothe gate of the selection transistor 54, a pixel signal caused by theamplifier transistor 53 appears in the vertical signal line VSL. On theother hand, when a selection control signal SEL of Low level is input tothe gate of the selection transistor 54, the appearance of the pixelsignal in the vertical signal line VSL is stopped. In this manner, onlythe output of a selected unit pixel 50 can be extracted from thevertical signal line VSL to which a plurality of the unit pixels 50 areconnected.

1.5 Layout Example of Color Filter

As described above, a color filter that selectively transmits lighthaving a particular wavelength is disposed on the photodiode PD in eachunit pixel 50. FIG. 5 is a diagram illustrating a layout example of thecolor filter according to the first embodiment. FIG. 5 illustrates alayout example of a color filter array that acquires an IR image inaddition to a color image of three primary colors of RGB.

As illustrated in FIG. 5, for example, a color filter array 60 has aconfiguration in which patterns of 2×2 pixels as units of repetition incolor filter arrangement (hereinafter referred to as “unit patterns”) 61are arranged in a two-dimensional grid pattern.

For example, each unit pattern 61 includes four color filters in total,that is, a color filter 107R that selectively transmits light having awavelength component of red (R), a color filter 107G that selectivelytransmits light having a wavelength component of green (G), a colorfilter 107B that selectively transmits light having a wavelengthcomponent of blue (B), and a color filter 107IR that selectivelytransmits light having a wavelength component of IR light.

FIG. 5 exemplifies a layout of the unit pattern 61 in which the colorfilter 107G is disposed on the upper left, the color filter 107R isdisposed on the upper right, the color filter 107B is disposed on thelower left, and the color filter 107IR is disposed on the lower right,but the layout is not limited to such arrangement.

In FIG. 5 and in the following description, the color filter array 60including the color filter 107IR based on Bayer arrangement isexemplified, but the basic color filter arrangement is not limited toBayer arrangement. For example, the color filter arrangement can bebased on various kinds of color filter arrangement, such as X-Trans(registered trademark) color filter arrangement having a unit pattern of3×3 pixels, quad Bayer arrangement having a unit pattern of 4×4 pixels,and white RGB color filter arrangement in which a unit pattern is 4×4pixels including a color filter having broad light transmissioncharacteristics for a visible light region (hereinafter also referred toas “clear” or “white”) in addition to color filters for three primarycolors of RGB. The same applies to other embodiments described later.

1.6 Stacked Structure Example of Solid-State Imaging Device

FIG. 6 is a diagram illustrating a stacked structure example of a CMOSimage sensor according to the first embodiment. As illustrated in FIG.6, a CMOS image sensor 10 has a structure in which a photoreceiver chip71 and a circuitry chip 72 are vertically stacked. The photoreceiverchip 201 is, for example, a semiconductor chip including the pixel array11 in which the photodiodes PD are arranged. The circuitry chip 72 is,for example, a semiconductor chip in which the pixel circuitsillustrated in FIG. 5 are arranged.

For bonding of the photoreceiver chip 71 and the circuitry chip 72, forexample, what is called “direct bonding”, in which bonding surfaces ofthe chips are planarized and the chips are bonded by interelectronicforce, can be used. However, the bonding method is not limited thereto,and, for example, what is called Cu-Cu bonding, where electrode padsmade of copper (Cu) formed on bonding surfaces are bonded, and othertypes of bonding, such as bump bonding, can be used.

For example, the photoreceiver chip 71 and the circuitry chip 72 areelectrically connected to each other through a connection portion suchas a through-silicon via (TSV) passing through the semiconductorsubstrate. Examples of methods that can be employed for connection usingthe TSV include what is called a twin TSV method in which two TSVs of aTSV provided in the photoreceiver chip 71 and a TSV provided in a regionfrom the photoreceiver chip 71 to the circuitry chip 72 are connected onthe outer surface of the chip, and what is called a shared TSV method inwhich the photoreceiver chip 71 and the circuitry chip 72 are connectedby a TSV passing through the photoreceiver chip 71 and the circuitrychip 72.

When Cu-Cu bonding or bump bonding is used for the bonding of thephotoreceiver chip 71 and the circuitry chip 72, the photoreceiver chip71 and the circuitry chip 72 are electrically connected to each otherthrough a Cu-Cu bonding portion or a bump bonding portion.

1.7 Cross-Sectional Structure Example of Unit Pixel

Next, a cross-sectional structure example of the unit pixel according tothe first embodiment is described in detail with reference to thedrawings. FIG. 7 is a cross-sectional diagram illustrating across-sectional structure example of a CMOS image sensor according tothe first embodiment. For simple description, FIG. 7 illustrates across-sectional structure example of the photoreceiver chip 71 in FIG.6, and omits a cross-sectional structure example of the circuitry chip72. In FIG. 7, wiring layers constituting electrical connection from thetransfer transistor 51 and the photoreceiver chip 71 to the circuitrychip 72 are also omitted. For the sake of description, FIG. 7exemplifies a case where four unit pixels 50G, 50B, 50R, and 501Rconstituting the unit pattern 61 are arranged in a row along the crosssection.

In the following description, latter indexes (alphabets or alphabets andnumerals) such as ‘R’, ‘G’, ‘G1’, ‘G2’, ‘B’, or ‘IR’ added to the firstnumeral in reference symbols are omitted and only the numerals in thefirst half are used, unless the configurations are distinguished. Forexample, when the unit pixels 50G, 50B, 50R, and 501R are notdistinguished, the reference symbols thereof are ‘50’. Similarly, whenthe color filters 107G, 107B, 107R, and 107IR are not distinguished, thereference symbols thereof are ‘107’.

FIG. 7 illustrates a cross-sectional structure example of the unit pixel50 in the back-illuminated CMOS image sensor 10. As illustrated in FIG.7, each unit pixel 50 includes a semiconductor substrate 100, aninsulator film 103 provided on the back surface (top surface in FIG. 7)of the semiconductor substrate 100, an anti-reflection film 104 providedon the insulator film 103, an insulator film 105 provided on theanti-reflection film 104, a color filter 107 provided on the insulatorfilm 105, an on-chip lens 108 provided on the color filter 107, and apassivation film 109 that protects the surface of the on-chip lens 108.

For the insulator film 103, for example, insulating material such asaluminum oxide (Al₂O₃) can be used. For the anti-reflection film 104,for example, high refractive index material such as tantalum pentoxide(Ta₂O₅) can be used. For the insulator film 105, for example, insulatingmaterial such as silicon oxide (SiO₂) can be used.

In the semiconductor substrate 100, for example, N-type semiconductorregions 101 formed by diffusing N-type dopants in rectangular regionsarranged in the back surface in a two-dimensional grid pattern, and aP-type semiconductor region 102 surrounding the N-type semiconductorregions 101 are provided. The N-type semiconductor regions 101 and theP-type semiconductor region 102 constitute a photodiode PD as aphotoelectric conversion element.

On the insulator film 105 between the unit pixels 50, a shielding film106 that reduces leakage of light, having obliquely entered a unit pixel50, into a photodiode PD in another unit pixel (hereinafter alsoreferred to as “adjacent pixel”) 50 adjacent to the unit pixel 50 isprovided. For the shielding film 106, for example, tungsten (W) can beused.

Furthermore, a trench is formed between the unit pixels 50 in thesemiconductor substrate 100 so as to separate adjacent photodiodes PD.For example, the inside of the trench may be filled with the insulatorfilm 105. In this case, a gap may remain in a center part of theinsulator film 105 in the trench. In the following description, theinsulator film 105 in the trench is referred to as “pixel separationportion”.

The trench may reach the front surface of the semiconductor substrate100 from the back surface thereof, and may be formed to the middle fromthe back surface of the semiconductor substrate 100. In the followingdescription, the configuration in which the trench reaches the frontsurface of the semiconductor substrate 100 from the back surface thereofis referred to as “front full trench isolation (FFTI)”, and theconfiguration in which the trench is formed in the middle from the backsurface of the semiconductor substrate 100 is referred to as “reversedeep trench isolation (RDTI)”.

On the top surface of the insulator film 105, a color filter 107 isprovided for each unit pixel 50. Specifically, a unit pixel 50R thatgenerates a pixel signal related to a wavelength component of red (R) isprovided with a color filter 107R that selectively transmits lighthaving the wavelength component of red. A unit pixel 50G that generatesa pixel signal related to a wavelength component of green is providedwith a color filter 107G that selectively transmits light having thewavelength component of green (G). A unit pixel 50B that generates apixel signal related to a wavelength component of blue is provided witha color filter 107G that selectively transmits light having thewavelength component of blue (B). A unit pixel 501R that generates apixel signal related to IR light is provided with a color filter 107IRthat selectively transmits light having a wavelength component of IRlight.

On the color filter 107, an on-chip lens 108 is provided for each unitpixel 50. For example, the radius of curvature of each on-chip lens 108is set such that incident light is concentrated at substantially thecenter of a light incident surface of the photodiode PD. For example,the surface of the on-chip lens 108 is covered with the passivation film109 such as a TEOS film.

In the configuration described above, a plurality of pillar-shapedstructures (hereinafter simply referred to as “pillars”) 110 areprovided on the top surface of the insulator film 105 so as to protrudeto the inside of the color filter 107. For example, as exemplified inFIG. 8, the pillars 110 are provided on the insulator film 105 of theunit pixels 50R, 50G, and 50B that generate a color image of threeprimary colors of RGB. In FIG. 8, the illustration of structures oflayers upper than the color filter 107 is omitted.

1.8 Shape of Pillar

For example, each pillar 110 may be a columnar structure. The pillar 110is not limited to a column, and may be variously modified to, forexample, an elliptic column, polygonal columns of a triangular prism orhigher (including rectangular parallelepiped), circular truncated cones(including elliptic truncated cone), polygonal truncated cones of atriangular truncated cone or higher, cones (including elliptic cone),and polygonal cones of a triangular cone or higher.

1.9 Arrangement of Pillars

The pillars 110 may be arranged in square arrangement on the surface ofthe insulator film 105 as exemplified in FIG. 9, for example, and, forexample, may be arranged in hexagonal close-packed arrangement asexemplified in FIG. 10. The arrangement is not limited to squarearrangement and hexagonal close-packed arrangement, and can be variouslymodified to, for example, random arrangement in which the distances(pitches) between the pillars 110 are irregular.

1.10 Wavelength Selection Function by Pillars

By appropriately selecting the diameter, the pitch, and the material ofthe pillars 110 having the configuration and the arrangement describedabove, the pillars 110 can function as a wavelength selection element(wavelength filter) that allows light in a particular wavelength band tobe absorbed or transmitted. The diameter may be the diameter of the topsurface or the bottom surface of a columnar or conical structure. Thepitch may be a distance between center axes of adjacent pillars 110. Inthe following description, the pillars functioning as a wavelengthfilter are referred to as “pillar array”.

FIG. 11 is a diagram for explaining the wavelength selection function ofthe pillar array according to the first embodiment. As illustrated inFIG. 11, the light absorptance of the pillar array tends to be higher asthe pitch between the pillars 110 becomes smaller and be higher as thediameter of each pillar becomes larger.

On the other hand, the wavelength of light absorbed by the pillar arraytends to be shorter as the pitch between the pillars 110 becomes smallerand be shorter as the diameter of each pillar 110 becomes smaller. The“wavelength of light absorbed by the pillar array” as used herein may bea wavelength at which the absorptance peaks in a light absorptionspectrum of the pillar array, in other words, a wavelength at which thetransmittance becomes lowest in the light transmission spectrum of thepillar array.

As examples, FIG. 12 illustrates some light transmission spectra of thepillar array. Light transmission spectra SP1 to SP8 exemplified in FIG.12 are light transmission spectra measured when pillars 110 havinguniform diameters and pitches are used. For example, the diameters andthe pitches of the pillar array are designed so as to shift from thelower right to the upper left in FIG. 11 in the order from the lighttransmission spectra SP1 to SP8.

As illustrated in FIG. 12, the pillar array configured by the pillars110 can function as a wavelength filter having a light transmissionspectrum to selectively absorb light in a particular wavelength band.Thus, by appropriately setting the diameter and/or the pitch of thepillars 110 constituting the pillar array, a wavelength filter thatselectively attenuates light in an intended wavelength band can beimplemented.

As mentioned above, the pillar array can function as not only awavelength filter that selectively absorbs light in a particularwavelength band (hereinafter referred to as “particular wavelengthabsorption filter”) but also a wavelength filter that selectivelytransmits light in a particular wavelength band (hereinafter referred toas “particular wavelength transmission filter”).

FIG. 13 is a diagram illustrating an example of the relation between thediameter of the pillars and the wavelength of light absorbedby/transmitted through the pillar array according to the firstembodiment. FIG. 13 exemplifies a case where the pitch between thepillars 110 in the pillar array is four times the diameter of thepillars 110 (pitch/diameter=4). In the following description, awavelength of light at which the absorptance of the pillar array forms apeak is referred to as “absorption peak wavelength”, and a wavelength oflight at which the transmittance of the pillar array forms a peak isreferred to as “transmission peak wavelength”.

In FIG. 13, a line WV indicates an absorption peak wavelength when thepillar array is designed as a particular wavelength absorption filter,and a line WT indicates a transmission peak wavelength when the pillararray is designed as a particular wavelength transmission filter. InFIG. 13, a broken line R indicates the center wavelength of light of red(R), a broken line G indicates the center wavelength of light of green(G), and a broken line B indicates the center wavelength of light ofblue (B).

As illustrated in FIG. 13, in both the cases where the pillar array isdesigned as a particular wavelength absorption filter and the pillararray is designed as a particular wavelength transmission filter, theabsorption peak wavelength or the transmission peak wavelength tends tobe longer as the diameter of the pillars 110 becomes larger.

From FIG. 13, for example, it is understood that the diameter of eachpillar 110 is desirably about 120 nanometers (nm) when the pillar arrayfunctions as a particular wavelength transmission filter thatselectively transmits light having a wavelength component of red (R),and desirably about 100 nm when the pillar array functions as aparticular wavelength absorption filter that selectively absorbs lighthaving a wavelength component of red (R). Similarly, for example, it isunderstood that the diameter of each pillar 110 is desirably about 100nm when the pillar array functions as a particular wavelengthtransmission filter that selectively transmits light having a wavelengthcomponent of green (G), and desirably about 80 nm when the pillar arrayfunctions as a particular wavelength absorption filter that selectivelyabsorbs light having a wavelength component of green (G). Furthermore,for example, it is understood that the diameter of each pillar 110 isdesirably about 80 nm when the pillar array functions as a particularwavelength transmission filter that selectively transmits light having awavelength component of blue (B), and desirably about 60 nm when thepillar array functions as a particular wavelength absorption filter thatselectively absorbs light having a wavelength component of blue (B).

The specific numerals illustrated in FIG. 13 are merely examples, andmay be values that change depending on various conditions such as thematerial of the pillars 110 and the materials of the color filter 107and other films.

1.11 Pillar Array in First Embodiment

In the first embodiment, for example, in order to attenuate IR lighthaving a particular wavelength entering the photodiodes PD in the unitpixels 50R, 50G, and 50B that acquire a color image of three primarycolors of RGB, the pillars 110 constituting a pillar array are designedso as to selectively absorb IR light having the particular wavelength.

In this manner, by providing the pillar array that absorbs IR lighthaving the particular wavelength to the unit pixels 50R, 50G, and 50B,the color mixture caused by the incidence of IR light to the unit pixels50R, 50G, and 50B can be reduced to acquire a color image having highcolor reproducibility.

1.12 Position of Pillar Array

The positions of the pillars 110 constituting the pillar array can bevariously modified to, for example, positions closer to a photodiode PDin the color filter 107 (see, for example, FIG. 7), as long as thepositions are included in a region from the front surface (lightincident surface) of the on-chip lens 108, which is the topmost layer,to the light incident surface of the photodiode PD.

For example, the height of each pillar 110 can be set to about 300 nm.The height is not limited thereto, and may be larger or smaller than thethickness of the color filter 107.

1.13 Material of Pillar

For the material of the pillar 110 according to the first embodiment,for example, material having a refractive index of 1.5 or more can beused. Examples of the materials satisfying the condition include silicon(Si), germanium (Ge), gallium phosphide (GaP), aluminum oxide (Al₂O₃),cerium oxide (CeO₂), hafnium oxide (HfO₂), indium oxide (In₂O₃), tinoxide (SnO₂), niobium pentoxide (Nb₂O₅), magnesium oxide (MgO), tantalumpentoxide (Ta₂O₅), titanium pentoxide (Ti₃O₅), other kinds of titaniumoxide (such as TiO and TiO₂), tungsten oxide (WO₃), yttrium oxide(Y₂O₃), zinc oxide (ZnO), zirconia (ZrO₂), cerium fluoride (CeF₃),gadolinium fluoride (GdF₃), lanthanum fluoride (LaF₃), and neodymiumfluoride (NdF₃).

The crystal structure of the pillar 110 may be a single crystal or apolycrystal of the above-mentioned materials. Alternatively, the pillar110 may have an amorphous structure without a crystal structurecompletely or incompletely.

1.14 Diameter and Pitch of Pillars

Next, the diameter and pitch of the pillars 110 are described by way ofexample. In this description, an example in which the shape of eachpillar 110 is columnar and the arrangement thereof is hexagonalclose-packed arrangement is described. For example, the followingdescription can also be applied to square arrangement and other types ofarrangement.

For example, the diameter of each pillar 110 can be set in the range of30 to 200 nm such that the absorption peak wavelength of the pillararray substantially matches a particular wavelength of IR light. Forexample, the pitch between the pillars 110 can be set in the range of200 to 1,000 nm such that absorptance of IR light having a particularwavelength is sufficiently obtained. For example, in the case ofabsorbing and attenuating IR light having a wavelength of 940 nm, thediameter of the pillar 110 can be set in the range of 180 to 220 nm, andthe pitch between the pillars 110 can be set to 632 nm.

Comparing the case where gallium phosphide (GaP) having a refractiveindex of 3.18 for light having a wavelength of 800 nm is used as thematerial of the pillars 110 and the case where silicon (Si) having arefractive index of 3.69 for light having a wavelength of 800 nm is usedas the material of the pillars 110, for example, the refractive index ofsilicon (Si) is about 0.86 times the refractive index of galliumphosphide (GaP). Thus, by setting the diameter and the pitch designed onthe assumption that gallium phosphide (GaP) is used to about 0.86 times,the diameter and the pitch in the case of using silicon (Si) can bedetermined.

Similarly, the diameter and the pitch in the case of using anothermaterial can be calculated from the above-mentioned diameter and pitchin the case of using gallium phosphide (GaP) and/or the above-mentioneddiameter and pitch in the case of using silicon (Si) based on therefractive index of the material.

In the present example, the case where the pillar 110 has a columnarshape has been exemplified. However, for example, when the shape of thepillar 110 is a rectangular parallelepiped the upper base of which issquare, the value of the diameter described above may be applied to thelength of one side of the upper base or the length of a diagonal passingthrough the center point of the upper base. When the pillar 110 is apolygonal column, for example, the value of the diameter described abovemay be applied to the length of a diagonal passing through the centerpoint of the upper base.

Furthermore, when the pillar 110 is an elliptical column, for example,the value of the diameter described above may be applied to the lengthof the major axis, the length of the minor axis, or the average lengthof the major axis and the minor axis of the upper base.

1.15 Manufacturing Method for Pillar

Next, a manufacturing method for the pillar 110 according to the firstembodiment is described by way of example. FIG. 14 to FIG. 19 arediagrams illustrating the manufacturing method for the pillar accordingto the first embodiment. In this description, the photodiode PD formedfrom the N-type semiconductor region 101 and the P-type semiconductorregion 102, and the insulator film 103, on the back surface of thesemiconductor substrate 100, the anti-reflection film 104, and theinsulator film 105 (including the inside of the trench) have alreadybeen formed on the semiconductor substrate 100. The order of theformation of the shielding film 106 may be before or after the formationof the pillar 110.

In this manufacturing process, first, as illustrated in FIG. 14, amaterial film 110A made of the material of the pillar 110 is formed onthe insulator film 105 formed on the back surface side of thesemiconductor substrate 100. For the formation of the material film110A, for example, various kinds of film forming methods such aschemical vapor deposition (CVD), plasma CVD, and sputtering can be used.For example, the thickness of the material film 110A may besubstantially equal to or larger than the height of the pillar 110.

Next, a resist solution such as diluted high-resolution electron beamresist (ZEP) containing conductive polymers is spin-coated on thematerial film 110A. Subsequently, as illustrated in FIG. 15, anarrangement pattern of the pillar 110 is transferred to the coatedresist solution by using electron beam lithography or photolithographyto form resist films R1 having the same arrangement pattern as thepillars 110.

Next, as illustrated in FIG. 16, the resist films R1 formed on thematerial film 110A are subjected to a descum process so that residuesand tailing after lithography are removed.

Next, as illustrated in FIG. 17, the material film 110A is etched whileusing the resist films R1 as a mask to process the material film 110A,so that the pillars 110 are formed. For the etching of the material film110A, deep etching technology such as deep reactive ion etching (DRIE)such as Bosch process can be used. After that, as illustrated in FIG.18, the resist films R1 left on the pillars 110 are removed by asking.

In this manner, the pillars 110 can be formed at the same step by usingthe resist films R1 formed at the same step as a mask. The same appliesto a case where pillars having different diameters and pitches are mixedas in an embodiment described later, and hence the manufacturing processcan be facilitated.

Next, as illustrated in FIG. 19, material such as spin-on glass (SOG) isspin-coated on the insulator film 105 on which the pillars 110 areformed, and the material is cured to form a color filter 107. The colorfilter 107 may be formed by using CVD or plasma CVD instead of spincoating.

Through the steps as described above, the pillars 110 buried in thecolor filter 107 are formed on the insulator film 105 formed on the backsurface side of the semiconductor substrate 100.

1.16 Actions and Effects

As described above, according to the first embodiment, the pillar arraythat absorbs IR light having a particular wavelength is provided to theunit pixels 50R, 50G, and 50B that acquire a color image, and hence thecolor mixture caused by the incidence of IR light can be reduced toacquire image data having high color reproducibility.

In the first embodiment, the pillars 110 constituting the pillar arraythat absorbs IR light having a particular wavelength are buried in thecolor filters 107R, 107G, and 107B. Thus, the increase in height of thecolor filters can be suppressed as compared with the structure in whichcolor filters are stacked. Consequently, the leakage of light that hasentered a unit pixel 50 to an adjacent pixel can be reduced to acquireimage data having higher color reproducibility.

2. Second Embodiment

In the above-mentioned first embodiment, the case where the pillars 110constituting the pillar array that absorbs IR light have the samediameter and the pillars 110 are arranged with uniform pitches has beenexemplified. The pillar array that absorbs IR light is not limited tosuch a configuration.

For example, as in a CMOS image sensor 10-2 exemplified in FIG. 20, aplurality of kinds (two kinds in FIG. 20) of pillars 211 and 212 havingrandomly different diameters may be mixed.

For example, the mixed kinds of pillars 211 and 212 may be arrangementin which pitches between the pillars are irregularly random asexemplified in FIG. 21.

In the following description, the state in which the diameters ofpillars are “random” refers to a state in which two or more kinds ofdifferent diameters are mixed in a plurality of pillars, and the statein which the pitches between the pillars are “random” refers to a statein which two or more kinds of different pitches are mixed among aplurality of pillars.

In this manner, by randomly arranging a plurality of kinds of pillars(for example, the pillars 211 and 212) having different diameters, apillar array having broad light absorption characteristics or lighttransmission characteristics to incident light can be implemented.

Consequently, not only IR light having a particular wavelength but alsoIR light in a broad wavelength band can be attenuated, and hence themixing of colors caused by incidence of IR light can be further reducedto acquire image data having further improved color reproducibility.

Other configurations, operations, and effects may be the same as thosein the above-mentioned embodiment, and hence the detailed descriptionsthereof are herein omitted.

3. Third Embodiment

As mentioned in the first embodiment, the shape of each pillar 110 isnot limited to a column, and can be variously modified to, for example,an elliptic column, polygonal columns of a triangular prism or higher(including rectangular parallelepiped), circular truncated cones(including elliptic truncated cone), polygonal truncated cones of atriangular truncated cone or higher, cones (including elliptic cone),and polygonal cones of a triangular cone or higher.

For example, by shaping the pillars such that the diameter graduallychanges from the bottom surface (insulator film 105 side) toward the topsurface or the apex (this shape is also referred to as “tapered shape”),as the pillars 310 exemplified in FIG. 22, the wavelength of light to beabsorbed or transmitted can be changed for each height. Thus, a pillararray having broad light absorption characteristics or lighttransmission characteristics for incident light can be implemented.

Consequently, similarly to the second embodiment, not only IR lighthaving a particular wavelength but also IR light in a broad wavelengthband can be attenuated, and hence the mixing of colors caused byincidence of IR light can be further reduced to acquire image datahaving further improved color reproducibility.

When the pillar 310 has a tapered shape in which the diameter decreasestoward the top surface, for example, the angle (elevation angle) of theinclined surface in the case where the top surface of the insulator film105 is a horizontal surface can be set in the range of 45 degrees ormore and less than 90 degrees. On the other hand, when the pillar 310has a tapered shape in which the diameter increases toward the topsurface, for example, the angle (elevation angle) of the inclinedsurface in the case where the top surface of the insulator film 105 is ahorizontal surface can be set in the range of more than 90 degrees and135 degrees or less.

For the shape in which the diameter gradually changes from the bottomsurface (insulator film 105 side) toward the top surface or the apex, asmentioned above in the first embodiment, for example, various kinds ofshapes such as circular truncated cones (including elliptic truncatedcone), polygonal truncated cones of a triangular truncated cone orhigher, cones (including elliptic cone), and polygonal cones of atriangular cone or higher can be employed.

The shape from the bottom surface (insulator film 105 side) toward thetop surface or the apex is not limited to the shape (tapered shape) inwhich the diameter gradually changes, and may be variously changed to,for example, a shape in which the diameter changes step by step in astair-step form.

The shape as described above in which the diameter changes gradually orstep by step from the bottom surface (insulator film 105 side) towardthe top surface or the apex is not limited to the third embodiment, andcan be similarly applied to another embodiment described above ordescribed later.

Other configurations, operations, and effects may be the same as thosein the above-mentioned embodiments, and hence the detailed descriptionsthereof are herein omitted.

4. Fourth Embodiment

In the above-mentioned first to third embodiments, the case where thepillars 110, 211 and 212, or 310 are formed inside the color filter 107and on the insulator film 105 formed on the back surface side of thesemiconductor substrate 100 has been exemplified. However, as describedabove, the positions of the pillars 211 and 212, or 310 constituting apillar array can be variously modified as long as the positions areincluded in a region from the light incident surface (top surface) ofthe color filter 107 to the light incident surface of the photodiode PD.

For example, as in a CMOS image sensor 10-4 exemplified in FIG. 23, atleast a part of pillars 410 may be provided between the insulator film105 and the photodiode PD.

For example, the pillar 410 between the insulator film 105 and thephotodiode PD can be formed by forming a trench of a predetermined shapereaching the back surface of the semiconductor substrate 100 from thetop surface of the anti-reflection film 104 through the insulator film103 and filling the inside of the trench with predetermined material.

For example, the shape of the trench in which the pillar 410 is formedmay be the same shape as the pillars 110, 211 and 212, or 310exemplified in the above-mentioned first to third embodiments.

The material filled in the trench, that is, the material of the pillar410, may be the same as or different from the material of the insulatorfilm 105. For example, the insulator film 105 and the pillar 410 may bemade of insulating material such as silicon oxide (SiO₂) or theinsulator film 105 may be made of insulating material such as siliconoxide (SiO₂), and the pillar 410 may be made of silicon (Si) or galliumphosphide (GaP).

When the pillar 410 is made of the same material as the insulator film105, the pillar 410 and the insulator film 105 can be manufactured atthe same step.

Furthermore, it is preferred that the material used for the pillar 410be insulating material. However, when the inner surface of the trench iscovered with an insulator film, the material used for the pillar 410 isnot limited to insulating material. In this case, the same material asthe material of the pillar 110 exemplified in the first embodiment maybe used for the pillar 410.

With the configuration described above, similarly to the firstembodiment, the leakage of light to an adjacent pixel due to theincreased height can be suppressed while the incidence of IR light tothe unit pixels 50R, 50G, and 50B that acquire color images issuppressed, and hence image data having high color reproducibility canbe acquired.

Other configurations, operations, and effects may be the same as thosein the above-mentioned embodiments, and hence the detailed descriptionsthereof are herein omitted.

5. Fifth Embodiment

In the above-mentioned first to fourth embodiments, the case where thecolor filters 107R, 107G, and 107B for the unit pixels 50R, 50G, and 50Bthat acquire color images of three primary colors of RGB are formed,respectively, so as to contact the top surface of the insulator film 105formed on the back surface side of the semiconductor substrate 100 hasbeen exemplified. However, the color filters are not limited to such aconfiguration.

For example, as in a CMOS image sensor 10-5 exemplified in FIG. 24, forexample, a planarization film 501 made of insulating material such assilicon nitride (SiN) may be provided on the top surface of theinsulator film 105 formed on the back surface side of the semiconductorsubstrate 100, and the color filters 107R, 107G, and 107B may bedisposed on the planarization film 501.

In this case, it is desired that the heights of the light incidentsurfaces (top surfaces) of the color filters 107R, 107G, and 107Bsubstantially match the height of the light incident surface (topsurface) of the color filter 107R on the upper layer side in the colorfilter 107IR. In this manner, the surface on which the on-chip lens 108is formed can be planarized, and hence the manufacturing precision ofthe on-chip lens 108 can be improved.

In the fifth embodiment, for example, when the first to thirdembodiments are based (FIG. 24 illustrates a case based on the firstembodiment), for example, the pillars 110, 211 and 212, or 310 may beformed inside the planarization film 501 and on the insulator film 105formed on the back surface side of the semiconductor substrate 100.

With the configuration described above, similarly to the firstembodiment, the incidence of IR light to the unit pixels 50R, 50G, and50B that acquire color images can be suppressed, and hence image datahaving high color reproducibility can be acquired.

Other configurations, operations, and effects may be the same as thosein the above-mentioned embodiments, and hence the detailed descriptionsthereof are herein omitted.

6. Sixth Embodiment

In the above-mentioned first to fifth embodiments, the case where thecolor filter 107IR having the structure in which two color filters 107Rand 107B are stacked is used as a color filter that selectivelytransmits IR light has been exemplified. However, the color filter isnot limited to such a configuration.

For example, as in a CMOS image sensor 10-6 exemplified in FIG. 25, inthe unit pixel 501R, a plurality of pillars 610 constituting a pillararray configured to selectively transmit IR light, in other words,capable of broadly absorbing light in a visible light region as a whole,may be provided on the insulator film 105 instead of the color filter107IR having the structure in which two color filters 107R and 107B arestacked.

With such a configuration, the height of the entire color filter 107 canbe decreased, and hence the leakage of light that has entered a unitpixel 50 to an adjacent pixel 50 can be further reduced. As a result,the color reproducibility of acquired image data can be furtherimproved.

In FIG. 25, the case based on the cross-sectional structure of the CMOSimage sensor 10 according to the first embodiment has been exemplified.However, the sixth embodiment is not limited to the first embodiment butmay be based on another embodiment.

Other configurations, operations, and effects may be the same as thosein the above-mentioned embodiments, and hence the detailed descriptionsthereof are herein omitted.

7. Seventh Embodiment

In the above-mentioned first to sixth embodiments, the case where thepillar array that selectively absorbs IR light is disposed in the unitpixels 50R, 50G, and 50B that acquire color images of three primarycolors of RGB has been exemplified. On the other hand, in a seventhembodiment, a case where the color filter 107 and the pillar array arecombined to shape the wavelength spectrum of light entering thephotodiodes PD in the unit pixels 50R, 50G, and 50B is described by wayof examples. In the following description, a case based on the firstembodiment is exemplified, but the basic embodiment is not limited tothe first embodiment, and may be another embodiment described above ordescribed later.

As described above, the pillar array configured by the pillars 110 canfunction as a particular wavelength absorption filter that selectivelyabsorbs light having a particular wavelength, by changing the diameterof each pillar 110 and the pitch between the pillars 110.

In view of the above, in the seventh embodiment, as in a CMOS imagesensor 10-7 exemplified in FIG. 26, pillars 110R are disposed in theunit pixel 50R that receives light having a wavelength component of red(R), pillars 110G are disposed in the unit pixel 50G that receives lighthaving a wavelength component of green (G), and pillars 110B aredisposed in the unit pixel 50B that receives light having a wavelengthcomponent of blue (B).

As exemplified in FIG. 27, in a pillar array 700R configured by thepillars 110R, the diameter of each pillar 110R and the pitch between thepillars 110R are set such that light having a wavelength component ofred (R) is selectively transmitted. As exemplified in FIG. 28, in apillar array 700G configured by the pillars 110G, the diameter of eachpillar 110G and the pitch between the pillars 110G are set such thatlight having a wavelength component of green (G) is selectivelytransmitted. Furthermore, as exemplified in FIG. 29, in a pillar array700B configured by the pillars 110B, the diameter of each pillar 110Band the pitch between the pillars 110B are set such that light having awavelength component of blue (B) is selectively transmitted.

As understood from the comparison of FIG. 27 to FIG. 29, the diameter ofthe pillar 110R is the largest and the diameter of the pillar 110B isthe smallest among the pillars 110R, 110G, and 110B. This is because, asdescribed above in the first embodiment with reference to FIG. 11 toFIG. 13, when the diameter of the pillar 110 is increased, thetransmission peak wavelength or the absorption peak wavelength of thepillar array are shifted to the long wavelength side, and when thediameter of the pillar 110 is decreased, the transmission peakwavelength or the absorption peak wavelength of the pillar array areshifted to the short wavelength side.

FIG. 27 to FIG. 29 exemplify the case where the pitch in the pillararray configured by the pillars 110R, the pitch in the pillar arrayconfigured by the pillars 110G, and the pitch in the pillar arrayconfigured by the pillars 110B are the same. However, the pitches arenot limited the same pitch, and can variously modified.

FIG. 30 and FIG. 31 are diagrams illustrating examples of lighttransmission spectra when the color filter 107R that selectivelytransmits light having a wavelength component of red (R) is combinedwith the pillar array 700R configured by the pillars 110R havingdifferent diameters.

First, as illustrated in FIG. 30, when the color filter 107R is combinedwith a pillar array 700R designed such that the absorption peakwavelength is present on the shorter wavelength side than thetransmission peak wavelength of a light transmission spectrum SP107R ofthe color filter 107R, a light transmission spectrum SP R1 of awavelength filter configured by the color filter 107R and the pillararray 700R is shifted to the longer wavelength side as a whole than thelight transmission spectrum SP107R of the color filter 107R alone.

On the other hand, as illustrated in FIG. 31, when the color filter 107Ris combined with a pillar array 700R designed such that the absorptionpeak wavelength is present on the longer wavelength side than thetransmission peak wavelength of the light transmission spectrum SP107Rof the color filter 107R, a light transmission spectrum SP R2 of awavelength filter configured by the color filter 107R and the pillararray 700R is shifted to the shorter wavelength side as a whole than thelight transmission spectrum SP107R of the color filter 107R alone.

In this manner, by combining the color filter 107 and the pillar array,the wavelength spectrum of light transmitted through the color filter107 and the pillar array to enter the photodiode PD can be shaped.

In view of the above, for example, by combining the color filters 107that selectively transmit light having wavelength components of the samecolor with a pillar array that selectively absorbs a differentwavelength component, image data based on light beams that are of thesame type of color but at least a part of wavelength components of whichdo not overlap can be generated (multi-spectrum). For example, byproviding a unit pixel 50R in which the color filter 107R is combinedwith a pillar array 700R having a light transmission spectrum SP110R1exemplified in FIG. 30 and a unit pixel 50R in which the color filter107R is combined with a pillar array 700R having a light transmissionspectrum SP110R2 exemplified in FIG. 31, two pieces of image data basedon light beams that are of a color in the same red range but at least apart of wavelength components of which do not overlap can be generated.

The shaping of the wavelength spectrum described above with reference toFIG. 30 and FIG. 31 can be applied to not only the wavelength componentof red (R) but also other wavelength components of green (G) and blue(B) similarly.

As described above, in the seventh embodiment, by combining the colorfilter 107 and the pillar array, the wavelength spectrum of lighttransmitted through the color filter 107 and the pillar array to enterthe photodiode PD can be shaped. Consequently, the multi-spectrum ofimage data that can be acquired can be obtained, and hence image datahaving higher color reproducibility can be acquired.

As in the seventh embodiment, by combining a pillar array thatselectively absorbs light in a particular wavelength band with the colorfilter 107, light that has leaked from an adjacent pixel 50 can beattenuated similarly to the above-mentioned embodiments, and hence imagedata having higher color reproducibility can be acquired.

Other configurations, operations, and effects may be the same as thosein the above-mentioned embodiments, and hence the detailed descriptionsthereof are herein omitted.

8. Eighth Embodiment

Next, an eighth embodiment is described in detail with reference to thedrawings.

As exemplified in the above-mentioned embodiments, for example, as aconfiguration for acquiring color images of three primary colors of RGB,the configuration in which the unit pixels 50R, 50G, and 50B thatacquire the color images are provided with the color filters 107R, 107G,and 107B that selectively transmit wavelength components of allocatedcolors, respectively, can be employed.

However, in a general light absorbing color filter, its spectroscopiccharacteristics (light absorption spectrum) exhibit a gentle curve.Thus, light having wavelength components out of a wavelength band to betransmitted, in particular, light having a wavelength componentcorresponding to a boundary part thereof is not sufficiently attenuated,and colors are mixed among pixels responsible for different wavelengthcomponents. As a result, the color reproducibility may reduce.

In view of the above, in the eighth embodiment, a color filter and apillar array are combined so that spectroscopic characteristics of awavelength filter (hereinafter referred to as “combined filter”)configured by a combination of the color filter and the pillar array areadjusted, thereby improving the color reproducibility.

In the following description, the case based on the first embodiment isexemplified. The basic embodiment is not limited to the firstembodiment, and may be another embodiment described above or describedbelow. In the following description, overlapping descriptions of thesame configurations, operations, and effects as the configurations,operations, and effects according to the above-mentioned embodiments areomitted by reference.

8.1 Layout Example of Color Filters

FIG. 32 is a diagram illustrating a layout example of color filtersaccording to the eighth embodiment. As illustrated in FIG. 32, forexample, Bayer arrangement is employed as color filter arrangement of acolor filter array 860 according to the eighth embodiment. Thus, forexample, this unit pattern 861 includes four color filters in total,that is, a color filter 107R that selectively transmits light having awavelength component of red (R), two color filters 107G that selectivelytransmits light having a wavelength component of green (G), and a colorfilter 107B that selectively transmits light having a wavelengthcomponent of blue (B).

However, the color filter arrangement that can be applied to the colorfilter array 860 according to the eighth embodiment is not limited toBayer arrangement. Similarly to the above-mentioned first embodiment,for example, various kinds of color filter arrangement such as X-Trans(registered trademark) color filter arrangement, quad Bayer arrangement,and white RGB color filter arrangement can be applied.

8.2 Cross-Sectional Structure Example of Unit Pixel

FIG. 33 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to the eighthembodiment. Similarly to FIG. 7 in the first embodiment, for example,FIG. 33 illustrates a cross-sectional structure example of thephotoreceiver chip 71 in FIG. 6, and omits a cross-sectional structureexample of the circuitry chip 72. In FIG. 33, wiring layers constitutingelectrical connection from the transfer transistor 51 and thephotoreceiver chip 71 to the circuitry chip 72 are also omitted. For thesake of description, FIG. 33 exemplifies a case where four unit pixels50B, 50R, 50G1, and 50G2 constituting a unit pattern 861 in Bayerarrangement are arranged in a row along the cross section.

As exemplified in FIG. 33, in a CMOS image sensor 10-8 according to theeighth embodiment, a color filter 107R in the unit pixel 50R thatgenerates a pixel signal based on light having a wavelength componentcorresponding to red is combined with a pillar array configured by aplurality of pillars 810R. Similarly, color filters 107G in the unitpixels 50G1 and 50G2 that generate pixel signals based on light having awavelength component corresponding to green are each combined with apillar array configured by a plurality of pillars 810G, and a colorfilter 107B in the unit pixel 50B that generates a pixel signal based onlight having a wavelength component corresponding to blue is combinedwith a pillar array configured by a plurality of pillars 810B.

For example, similarly to the pillars 110 in the first embodiment, thepositions of the pillars 810 may be on the top surface of the insulatorfilm 105 formed on the back surface side of the semiconductor substrate100 and inside the color filter 107. For example, the otherconfigurations may be the same as those in the cross-sectional structureexample of the unit pixel 50 describe above in the first embodiment withreference to FIG. 7.

8.3 Spectroscopic Characteristics of Combined Filters

FIG. 34 is a diagram for explaining spectroscopic characteristics (lighttransmission spectra) of the combined filters according to the eighthembodiment. As illustrated in FIG. 34, for example, in both a lighttransmission spectrum SP107B of the color filter 107B and a lighttransmission spectrum SP107G of the color filter 107G, the transmittanceof light near a boundary part R_BG is not sufficiently reduced, andcolors of light are mixed. Similarly, for example, in both the lighttransmission spectrum SP107G of the color filter 107G and a lighttransmission spectrum SP107R of the color filter 107R, the transmittanceof light near a boundary part R_GR is not sufficiently reduced, andcolors of light are mixed. The region near the boundary part may be awavelength region including a band of the boundary part and itsneighborhood band.

In view of the above, in the eighth embodiment, as exemplified in FIG.35, the color filter 107B is combined with a pillar array 800B(corresponding to the pillars 810B) that selectively absorbs light in awavelength band corresponding to the vicinity of the boundary part R_BG.The color filter 107R is combined with a pillar array 800R(corresponding to the pillars 810R) that selectively absorbs light in awavelength band corresponding to the vicinity of the boundary part R_GR.

On the other hand, the color filter 107G is combined with a pillar array800G (corresponding to the pillars 810G) in which a pillar array thatselectively absorbs light in a wavelength band corresponding to thevicinity of the boundary part R_BG and a pillar array that selectivelyabsorbs light in a wavelength band corresponding to the vicinity of theboundary part R_GR are combined.

In this manner, light transmitted through the combined filter and havinga wavelength component corresponding to the vicinity of the boundarypart R_BG and light transmitted through the combined filter and having awavelength component corresponding to the vicinity of the boundary partR_GR are attenuated, and hence the mixing of colors among pixels can bereduced to improve the color reproducibility.

The pillar array 800G may have a configuration in which the pillar array800B and the pillar array 800R are disposed on the same plane (topsurface of insulator film 105) as exemplified in FIG. 35, and may have aconfiguration in which the pillar array 800B and the pillar array 800Rare vertically stacked as exemplified in FIG. 36. When the pillar array800B and the pillar array 800R are vertically stacked, the pitch betweenthe pillars 810B constituting the pillar array 800B and the pitchbetween the pillars 810R constituting the pillar array 800R may besubstantially the same. Of the pillar array 800B and the pillar array800R, a pillar array having a larger diameter of the pillar 810 (forexample, pillar 810R) is desirably formed in the lower stage.

8.4 Actions and Effects

With the configuration described above, according to the eighthembodiment, light having wavelength components corresponding to thevicinity of a boundary part of light transmission spectra of differentcolor filters 107 can be sufficiently attenuated. Consequently, themixing of colors among pixels responsible for different wavelengthcomponents can be reduced to improve the color reproducibility ofacquired image data.

Other configurations, operations, and effects may be the same as thosein the above-mentioned embodiments, and hence the detailed descriptionsthereof are herein omitted.

9. Ninth Embodiment

In the above-mentioned eighth embodiment, the case where the pillararrays configured to absorb light having wavelength componentscorresponding to the vicinity of a boundary part in light transmissionspectra of different color filters 107 are combined with the colorfilter 107 has been described by way of examples. In a ninth embodiment,a case where a pillar array configured to absorb light having awavelength component corresponding to a tail part of a lighttransmission spectrum of a color filter 107 is combined with the colorfilter 107 is described by way of examples.

In the following description, the case based on the eighth embodiment isexemplified. The basic embodiment is not limited to the eighthembodiment, and may be another embodiment described above or describedbelow. In the following description, overlapping descriptions of thesame configurations, operations, and effects as the configurations,operations, and effects according to the above-mentioned embodiments areomitted by reference.

9.1 Spectroscopic Characteristics of Combined Filter

FIG. 37 is a diagram for explaining spectroscopic characteristics (lighttransmission spectra) of combined filters according to the ninthembodiment. As mentioned above in the eighth embodiment, it cannot besaid that the transmittance near a boundary part of light transmissionspectra of color filters 107 that selectively transmit light havingdifferent wavelength components is sufficiently reduced. However, thetransmittance of a tail part of the light transmission spectrum of thecolor filter 107 can be reduced by combining the color filter 107 with apillar array.

In view of the above, in the ninth embodiment, as illustrated in FIG.37, for example, light having a wavelength component at a tail part P_BGon the longer wavelength side in the light transmission spectrum of thecolor filter 107B that selectively transmits light having a wavelengthcomponent of blue (B), that is, on the green side, is attenuated byusing a pillar array. Similarly, light having a wavelength component ata tail part P_RG on the shorter wavelength side in the lighttransmission spectrum of the color filter 107R that selectivelytransmits light having a wavelength component of red (R), that is, onthe green side, is attenuated by using a pillar array.

In this manner, light having a wavelength component at the tail partP_BG in light entering the unit pixel 50B can be attenuated, and hencethe color reproducibility of a pixel signal generated by the unit pixel50G can be improved. Similarly, light having a wavelength component atthe tail part P_RG in light entering the unit pixel 50R can beattenuated, and hence the color reproducibility of a pixel signalgenerated by the unit pixel 50B can be improved.

9.2 Cross-Sectional Structure Example of Unit Pixel

FIG. 38 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to the ninthembodiment. For example, FIG. 38 illustrates a cross-sectioncorresponding to the cross section of the CMOS image sensor 10-8illustrated in FIG. 33 in the eighth embodiment.

In a CMOS image sensor 10-9 exemplified in FIG. 38, for example, in thesame configuration as in the CMOS image sensor 10-8 exemplified in FIG.33, the pillars 810G in the unit pixels 50G1 and 50G2 are omitted, andthe pillars 810R and 810B in the unit pixels 50R and 50B are replacedwith pillars 910R and 910B. The other configurations may be the same asin the CMOS image sensor 10-8 exemplified in FIG. 33.

9.3 Plan Layout Example of Pillars

FIG. 39 is a diagram illustrating a plan layout example of the pillars910 disposed in the color filters 107 in the unit pixels 50 constitutinga unit pattern in Bayer arrangement. As illustrated in FIG. 39, in theninth embodiment, a pillar array 900B (corresponding to the pillars910B) that selectively absorbs light having a wavelength component atthe tail part P_BG is disposed on the color filter 107B in the unitpixel 50B. A pillar array 900R (corresponding to the pillars 910R) thatselectively absorbs light having a wavelength component at the tail partP_RG is disposed on the color filter 107R in the unit pixel 50R. In thecolor filters 107G in the unit pixels 50G1 and 50G2, pillar arrays arenot necessarily required to be disposed.

9.4 Diameter and Pitch of Pillars

For example, the diameter of each pillar 910B constituting the pillararray 900B combined with the color filter 107B can be set in the rangeof 80 to 120 nm. For example, the pitch between the pillars 910B in thepillar array 900B can be set to 320 nm.

On the other hand, for example, the diameter of each pillar 910Rconstituting the pillar array 900R combined with the color filter 107Rcan be set in the range of 60 to 80 nm. For example, the pitch betweenthe pillars 910R in the pillar array 900R can be set to 320 nm.

However, the diameters of the pillars 910B and 910R and the pitchesbetween the pillars 910B or 910R are not limited to the above-mentionedvalues, and may be changed as appropriate depending on the materials ofthe pillars 910B and 910R.

9.5 Actions and Effects

With the configuration described above, according to the ninthembodiment, light having wavelength components corresponding to tailparts of light transmission spectra of different color filters 107 canbe sufficiently attenuated. Consequently, the mixing of colors amongpixels responsible for different wavelength components can be reduced toimprove the color reproducibility of acquired image data.

Other configurations, operations, and effects may be the same as thosein the above-mentioned embodiments, and hence the detailed descriptionsthereof are herein omitted.

10. Tenth Embodiment

In the above-mentioned ninth embodiment, the case where light having awavelength component at the tail part P_BG on the green side of thelight transmission spectrum of the color filter 107B that selectivelytransmits light having a wavelength component of blue (B) is attenuatedand light having a wavelength component at the tail part P_GR on thegreen side of the light transmission spectrum of the color filter 107Rthat selectively transmits light having a wavelength component of red(R) is attenuated to reduce the mixing of colors among pixelsresponsible for different wavelength components and improve the colorreproducibility of image data has been described by way of examples.

However, the method for reducing the mixing of colors among pixelsresponsible for different wavelength components to improve the colorreproducibility of image data is not limited to the method exemplifiedin the ninth embodiment. For example, as exemplified in FIG. 40, amethod for attenuating light having a wavelength component at a tailpart P_GB on the blue side and light having a wavelength component at atail part P_GR on the red side of the light transmission spectrum of thecolor filter 107B that selectively transmits light having a wavelengthcomponent of green (G) can be employed.

In this case, for example, as in a CMOS image sensor 10-10 exemplifiedin FIG. 41, the unit pixels 50G1 and 50G2 that generate pixel signalsbased on light having a wavelength component corresponding to green arecombined with a pillar array configured by a plurality of pillars 1010G.

For example, similarly to the pillars 110 in the first embodiment, thepositions of the pillars 1010G may be on the top surface of theinsulator film 105 formed on the back surface side of the semiconductorsubstrate 100 and inside the color filter 107.

In the color filter 107, in other words, the layout of a pillar array1000G configured by the pillars 1010G on the insulator film 105 can be,for example, similarly to the layout of the pillar array 800G describedabove in the eighth embodiment with reference to FIG. 35, a layout inwhich a plurality of pillars 1010GB constituting a pillar array thatselectively absorbs light in a wavelength band corresponding to a tailpart P_GB and a plurality of pillars 1010GR constituting a pillar arraythat selectively absorbs light in a wavelength band corresponding to atail part P_GR are combined. The pillars 1010GR and 1010GB correspond tothe pillars 1010G in FIG. 41.

In this manner, light transmitted through the combined filter and havinga wavelength component corresponding to the tail part P_GB and lighttransmitted through the combined filter and having a wavelengthcomponent corresponding to the tail part P_GR are attenuated. Thus, themixing of colors among pixels can be reduced to improve the colorreproducibility.

The pillar array 1000G is not limited to the configuration in which thepillar 1010GR and the pillar 1010GB are disposed in the same plane (topsurface of insulator film 105) as exemplified in FIG. 42, and may be,for example, the configuration in which the pillar array 1010GR and thepillars 1010GB are vertically stacked as described above in the eighthembodiment with reference to FIG. 36.

For example, the diameter of each pillar 1010GB can be set in the rangeof 60 to 80 nm. For example, the pitch between the pillars 1010GB can beset to 280 nm.

On the other hand, for example, the diameter of each pillar 1010GR canbe set in the range of 100 to 130 nm, and, for example, the pitchbetween the pillars 1010GR can be set to 400 nm.

However, the diameters of the pillars 1010GB and 1010GR and the pitchbetween the pillars 1010GB or 1010GR are not limited to theabove-mentioned values, and may be changed as appropriate depending onthe materials of the pillars 1010GB and 1010GR.

With the configuration described above, according to the tenthembodiment, light having wavelength components corresponding to thevicinity of a tail part of light transmission spectra of different colorfilters 107 can be sufficiently attenuated. Consequently, the mixing ofcolors among pixels responsible for different wavelength components canbe reduced to improve the color reproducibility of acquired image data.

Other configurations, operations, and effects may be the same as thosein the above-mentioned embodiments, and hence the detailed descriptionsthereof are herein omitted.

11. Eleventh Embodiment

The configuration according to the ninth embodiment and theconfiguration according to the tenth embodiment described above can becombined.

In this case, for example, as in a CMOS image sensor 10-11 exemplifiedin FIG. 43, a pillar array configured by a plurality of pillars 910R isdisposed in the unit pixel 50R, a pillar array configured by a pluralityof pillars 910B is disposed in the unit pixel 50B, and pillar arraysconfigured by a plurality of pillars 1010G (corresponding to 1010GR and1010GB) are disposed in the unit pixels 50G1 and 50G2.

For example, the plan layout of pillar arrays disposed in the colorfilters 107R, 107G, and 107B in the unit pixels 50R, 50G1, 50G2, and 50Bmay be, as exemplified in FIG. 44, a layout in which the plan layout ofthe pillar arrays 900R and 900B exemplified above in the ninthembodiment with reference to FIG. 39 and the plan layout of the pillararray 1000G exemplified above in the tenth embodiment with reference toFIG. 42 are combined. However, the pillar array 1000G is not limited tothe configuration in which the pillars 1010GR and the pillars 1010GB aredisposed in the same plane (top surface of insulator film 105), and maybe, for example, the configuration in which the pillar array 1010GR andthe pillars 1010GB are vertically stacked as described above in theeighth embodiment with reference to FIG. 36.

With the configuration described above, as exemplified in FIG. 45, lighthaving a wavelength component at the tail part P_BG in light enteringthe unit pixel 50B and light having a wavelength component at the tailpart P_RG in light entering the unit pixel 50R can be attenuated, andlight having wavelength components at tail parts P_GR and P_GB in lightentering the unit pixels 50G1 and 50G2 can be attenuated. Consequently,the mixing of colors among pixels responsible for different wavelengthcomponents can be further reduced to further improve the colorreproducibility of acquired image data.

Other configurations, operations, and effects may be the same as thosein the above-mentioned embodiments, and hence the detailed descriptionsthereof are herein omitted.

12. Twelfth Embodiment

Next, a twelfth embodiment is described in detail with reference to thedrawings.

When color filter arrangement such as quad Bayer arrangement in whichcolor filters 107 that transmit light having the same wavelengthcomponent are adjacent is employed, as an intrinsic problem, there maybe a case where a difference in sensitivity occurs between the unitpixel 50R or 50B to which the unit pixel 50G including the color filter107G on the side where the image height is higher is adjacent and theunit pixel 50R or 50B to which the unit pixel 50R or 50B including thecolor filter 107R or 106B that selectively transmits light having thesame wavelength component on the side where the image height is higheris adjacent. In other words, there may be a case where the difference insensitivity occurs between adjacent pixels 50 that generate pixelsignals based on light having the same wavelength component (hereinafterreferred to as “adjacent pixels 50 of same color”).

It is considered that this is because a part of light entering aphotodiode PD in the unit pixel 50R or 50B located on the side where theimage height is higher among the adjacent pixels 50 of the same color isabsorbed and attenuated by the color filter 107G adjacent on the sidewhere the image height is higher.

Such a problem becomes severe in a region where light obliquely entersand the image height is high.

In view of the above, in the twelfth embodiment, when color filterarrangement such as quad Bayer arrangement in which color filters 107that transmit light having the same wavelength component are adjacent isemployed, the difference in sensitivity caused between adjacent pixels50 provided with the color filters 107 that transmit light having thesame wavelength component can be reduced.

In the following description, a case where quad Bayer arrangement isemployed as color filter arrangement is exemplified. In the followingdescription, the case based on the eighth embodiment is exemplified. Thebasic embodiment is not limited to the eighth embodiment, and may beanother embodiment described above or described below. In the followingdescription, overlapping descriptions of the same configurations,operations, and effects as the configurations, operations, and effectsaccording to the above-mentioned embodiments are omitted by reference.

12.1 Layout of Pixel Array

FIG. 46 is a plan diagram illustrating a layout example of a pixel arrayaccording to the twelfth embodiment. As illustrated in FIG. 46, in thetwelfth embodiment, an effective pixel region 1201 in a pixel array 11in which a plurality of unit pixels 50 are arranged in accordance withquad Bayer arrangement is sectioned into a center region 1202 and aperipheral region 1203 based on the image height. The effective pixelregion 1201 may be a region in which unit pixels 50 that may be targetsfrom which pixel signals constituting image data are read are arranged.The center region 1202 may be, for example, a region in which the imageheight is 80% or less, and the peripheral region 1203 may be a region inwhich the image height is higher than 80%. However, these numerals aremerely specific examples, and can be variously changed.

12.2 Center Region

12.2.1 Layout of Unit Pattern

FIG. 47 is a diagram illustrating a plan layout of a unit pattern 1261belonging to the center region 1202 in FIG. 46. As illustrated in FIG.47, when color filter arrangement is quad Bayer arrangement, forexample, in the unit pattern 1261 in quad Bayer arrangement, unit pixels50G11 to 50G14 including a color filter 107G are disposed at four pixelsin total of 2×2 pixels located on the upper left, unit pixels 50R11 to50R14 including a color filter 107R are disposed at four pixels in totalof 2×2 pixels located on the upper right, unit pixels 50B11 to 50B14including a color filter 107B are disposed at four pixels in total of2×2 pixels located on the lower left, and unit pixels 50G15 to 50G18including a color filter 107G are disposed at four pixels in total of2×2 pixels located on the lower right.

12.2.2 Cross-Sectional Structure of Unit Pixel

FIG. 48 is a cross-sectional diagram illustrating a cross-sectionalstructure of a surface A-A in FIG. 47. FIG. 49 is a cross-sectionaldiagram illustrating a cross-sectional structure of a surface B-B inFIG. 47. Similarly to FIG. 7 in the first embodiment, for example, FIG.48 and FIG. 49 illustrate a cross-sectional structure example of thephotoreceiver chip 71 in FIG. 6, and omit a cross-sectional structureexample of the circuitry chip 72. In FIG. 48 and FIG. 49, wiring layersconstituting electrical connection from the transfer transistor 51 andthe photoreceiver chip 71 to the circuitry chip 72 are also omitted.

First, as illustrated in FIG. 48, in the surface A-A, the unit pixels50G11 and 50G12 and the unit pixels 50R11 and 50R12 are arranged. On theother hand, as illustrated in FIG. 49, in the surface B-B, the unitpixels 50B11 and 50B12 and the unit pixels 50G15 and 50G16 are arranged.

For example, the cross-sectional structures of the unit pixels 50G11 and50G12, 50R11 and 50R12, 50B11 and 50B12, and 50G15 and 50G16 may be thesame as a configuration obtained by omitting the pillars 110 from theunit pixel 50 exemplified above in the first embodiment with referenceto FIG. 7.

Such a cross-sectional structure may be similarly applied to the unitpixels 50R13 and 50R14, the unit pixels 50B13 and 50B14, and the unitpixels 50G13, 50G14, 50G17, and 50G18 (not shown).

In this manner, pillars are not provided in the color filter 107 in theunit pixel 50 belonging to the center region 1202. However, the pillarsare not necessarily required to be absent, and if needed, the pillarsmay be provided in the color filter 107.

12.3 Peripheral Region

12.3.1 Layout of Unit Pattern

FIG. 50 is a diagram illustrating a plan layout of a unit pattern 1262belonging to the peripheral region 1203 in FIG. 46. As illustrated inFIG. 50, when color filter arrangement is quad Bayer arrangement, forexample, in the unit pattern 1262 in quad Bayer arrangement, unit pixels50G21 to 50G24 including a color filter 107G are disposed at four pixelsin total of 2×2 pixels located on the upper left, unit pixels 50R21 to50R24 including a color filter 107R are disposed at four pixels in totalof 2×2 pixels located on the upper right, unit pixels 50B21 to 50B24including a color filter 107B are disposed at four pixels in total of2×2 pixels located on the lower left, and unit pixels 50G25 to 50G28including a color filter 107G are disposed at four pixels in total of2×2 pixels located on the lower right.

Of the unit pixels 50R21 to 50R24, in each of the unit pixels 50R22 and50R24, which are located on the side where the image height is higher,in other words, to which the unit pixels 50G including the color filter107G are adjacent on the side where the image height is higher, a pillararray configured by a plurality of pillars 1210R is provided.

Similarly, of the unit pixels 50B21 to 50B24, in each of the unit pixels50B22 and 50B24 located on the side where the image height is higher, apillar array configured by a plurality of pillars 1210B is provided.

12.3.2 Cross-Sectional Structure of Unit Pixel

FIG. 51 is a cross-sectional diagram illustrating a cross-sectionalstructure of a surface C-C in FIG. 50. FIG. 52 is a cross-sectionaldiagram illustrating a cross-sectional structure of a surface D-D inFIG. 50. Similarly to FIG. 48 and FIG. 49, for example, FIG. 51 and FIG.52 illustrate a cross-sectional structure example of the photoreceiverchip 71 in FIG. 6, and omit a cross-sectional structure example of thecircuitry chip 72. In FIG. 51 and FIG. 52, wiring layers constitutingelectrical connection from the transfer transistor 51 and thephotoreceiver chip 71 to the circuitry chip 72 are also omitted.

First, as in a cross-sectional structure of a CMOS image sensor 10-12exemplified in FIG. 51, in the surface C-C, the unit pixels 50G21 and50G22 and the unit pixels 50R21 and 50R22 are arranged. On the otherhand, as in a cross-sectional structure of the CMOS image sensor 10-12exemplified in FIG. 52, in the surface D-D, the unit pixels 50B21 and50B22 and the unit pixels 50G25 and 50G26 are arranged.

For example, the cross-sectional structures of the unit pixels 50G21 and50G22, 50R21, 50B21, and 50G25 and 50G26 may be the same as aconfiguration obtained by omitting the pillars 110 from the unit pixel50 exemplified above in the first embodiment with reference to FIG. 7.

Such a cross-sectional structure may be similarly applied to the unitpixel 50R23, the unit pixel 50B23, and the unit pixels 50G23, 50G24,50G27, and 50G28 (not shown).

On the other hand, in the unit pixel 50R22 and the unit pixel 50R24 (notshown), as described above, a pillar array configured by a plurality ofpillars 1210R is provided. Similarly, in the unit pixel 50B22 and theunit pixel 50B24 (not shown), a pillar array configured by a pluralityof pillars 1210B is provided. For example, similarly to the firstembodiment, the positions of the pillars 1210R and 1210B may be insidethe color filter 107 and on the insulator film 105 formed on the backsurface side of the semiconductor substrate 100.

12.4 Spectroscopic Characteristics of Pillar Array

The pillar arrays configured by the pillars 1210R provided in the unitpixels 50R22 and 50R24 are designed so as to function as a particularwavelength absorption filter that absorbs light leaking from a unitpixel 50G adjacent on the side where the image height is higher, forexample, light having a wavelength component of green (G). In view ofthe above, for the pillar array configured by the pillars 1210R, forexample, the pillar array 900R configured by the pillars 910Rexemplified in the ninth embodiment can be used.

On the other hand, the pillar arrays configured by the pillars 1210Bprovided in the unit pixels 50B22 and 50B24 are designed so as tofunction as a particular wavelength absorption filter that absorbs lightleaking from a unit pixel 50G adjacent on the side where the imageheight is higher, for example, light having a wavelength component ofgreen (G). In view of the above, for the pillar array configured by thepillars 1210B, for example, the pillar array 900B configured by thepillars 910B exemplified in the ninth embodiment can be used.

12.5 Actions and Effects

As described above, according to the twelfth embodiment, the leaking oflight to a unit pixel 50R or 50B to which a unit pixel 50G including acolor filter 107G on the side where the image height is higher from theunit pixel 50G can be reduced. Consequently, the difference insensitivity caused between adjacent pixels 50 provided with colorfilters 107 that transmit light having the same wavelength component canbe reduced to acquire color images having high color reproducibility.

Other configurations, operations, and effects may be the same as thosein the above-mentioned embodiments, and hence the detailed descriptionsthereof are herein omitted.

13. Thirteenth Embodiment

In the above-mentioned twelfth embodiment, the case where the effectivepixel region 1201 in the pixel array 11 is sectioned into the centerregion 1202 and the peripheral region 1203 based on the image height hasbeen exemplified. However, the effective pixel region 1201 may besectioned into a larger number of regions based on the image height.

For example, as exemplified in FIG. 53, the effective pixel region 1201may be sectioned into three regions, that is, the center region 1202 andthe peripheral region 1203 as well as an intermediate region 1304located between the center region 1202 and the peripheral region 1203.In this case, the intermediate region 1304 is a region surrounding thecenter region 1202, and the peripheral region 1203 is a regionsurrounding the intermediate region 1304.

13.1 Intermediate Region

13.1.1 Layout of Unit Pattern

FIG. 54 is a diagram illustrating a plan layout of a unit pattern 1363belonging to the intermediate region 1304 in FIG. 53. As illustrated inFIG. 54, when the color filter arrangement is quad Bayer arrangement,for example, in the unit pattern 1363 of the quad Bayer arrangement,unit pixels 50G31 to 50G34 provided with a color filter 107G aredisposed at four pixels in total of 2×2 pixels located on the upperleft, unit pixels 50R31 to 50R34 provided with a color filter 107R aredisposed at four pixels in total of 2×2 pixels located on the upperright, unit pixels 50B31 to 50B34 provided with a color filter 107B aredisposed at four pixels in total of 2×2 pixels located on the lowerleft, and unit pixels 50G35 to 50G38 provided with a color filter 107Gare disposed at four pixels in total of 2×2 pixels located on the lowerright.

Of the unit pixels 50R31 to 50R34, in each of the unit pixels 50R32 and50R34, which are located on the side where the image height is higher,in other words, to which the unit pixels 50G including the color filter107G are adjacent on the side where the image height is higher, a pillararray configured by a plurality of pillars 1310R is provided.

Similarly, of the unit pixels 50B31 to 50B34, in each of the unit pixels50B32 and 50B34 located on the side where the image height is higher, apillar array configured by a plurality of pillars 1310B is provided.

13.1.2 Cross-Sectional Structure of Unit Pixel

FIG. 55 is a cross-sectional diagram illustrating a cross-sectionalstructure of a surface E-E in FIG. 54. FIG. 56 is a cross-sectionaldiagram illustrating a cross-sectional structure of a surface F-F inFIG. 54. Similarly to FIG. 48 and FIG. 49, for example, FIG. 55 and FIG.56 illustrate a cross-sectional structure example of the photoreceiverchip 71 in FIG. 6, and omit a cross-sectional structure example of thecircuitry chip 72. In FIG. 55 and FIG. 56, wiring layers constitutingelectrical connection from the transfer transistor 51 and thephotoreceiver chip 71 to the circuitry chip 72 are also omitted.

First, as in the cross-sectional structure of a CMOS image sensor 10-13exemplified in FIG. 55, the unit pixels 50G31 and 50G32 and the unitpixels 50R31 and 50R32 are arranged in the surface E-E. On the otherhand, as in the cross-sectional structure of the CMOS image sensor 10-13exemplified in FIG. 56, the unit pixels 50B31 and 50B32 and the unitpixels 50G35 and 50G36 are arranged in the surface F-F.

For example, the cross-sectional structures of the unit pixels 50G31 and50G32, 50R31, 50B31, and 50G35 and 50G36 may be the same as aconfiguration obtained by omitting the pillars 110 from the unit pixel50 exemplified above in the first embodiment with reference to FIG. 7.

Such a cross-sectional structure may be similarly applied to the unitpixel 50R33, the unit pixel 50B33, and the unit pixels 50G33, 50G34,50G37, and 50G38 (not shown).

On the other hand, in the unit pixel 50R32 and the unit pixel 50R34 (notshown), as described above, a pillar array configured by a plurality ofpillars 1310R is provided. Similarly, in the unit pixel 50B32 and theunit pixel 50B34 (not shown), a pillar array configured by a pluralityof pillars 1310B is provided. For example, similarly to the firstembodiment, the positions of the pillars 1310R and 1310B may be insidethe color filter 107 and on the insulator film 105 formed on the backsurface side of the semiconductor substrate 100.

13.2 Spectroscopic Characteristics of Pillar Array

The pillar arrays configured by the pillars 1310R provided in the unitpixels 50R32 and 50R34 are designed so as to function as a particularwavelength absorption filter that absorbs light leaking from a unitpixel 50G adjacent on the side where the image height is higher, forexample, light having a wavelength component of green (G). In view ofthe above, for the pillar array configured by the pillars 1210R, forexample, the pillar array 900R configured by the pillars 910Rexemplified in the ninth embodiment can be used.

On the other hand, the pillar arrays configured by the pillars 1310Bprovided in the unit pixels 50B32 and 50B34 are designed so as tofunction as a particular wavelength absorption filter that absorbs lightleaking from a unit pixel 50G adjacent on the side where the imageheight is higher, for example, light having a wavelength component ofgreen (G). In view of the above, for the pillar array configured by thepillars 1310B, for example, the pillar array 900B configured by thepillars 910B exemplified in the ninth embodiment can be used.

However, the amount of light attenuated by the pillar arrays configuredby the pillars 1310R and 1310B may be lower than the amount of lightattenuated by the pillar arrays configured by the pillars 1210R and1210B according to the twelfth embodiment. In view of the above, in thethirteenth embodiment, the pillars 1310R or the pillars 1310B are formedin a region narrower than the regions where the pillars 1210R and thepillars 1210B are formed in each unit pixel 50 according to the twelfthembodiment.

13.3 Actions and Effects

With the configuration described above, the amount of light attenuatedby the pillar arrays configured by the pillars 1310R and 1310B can begradually increased from a region where the image height is low (centerregion 1202) to a region where the image height is high (peripheralregion 1203). Consequently, a pillar array having light absorptancecorresponding to the degree of light leakage from the unit pixel 50G canbe disposed in each unit pixel 50, and hence color images having highercolor reproducibility can be acquired.

In the above description, the case where the effective pixel region 1201is sectioned into two or three regions based on the image height hasbeen exemplified. The effective pixel region 1201 is not limited to theexamples, and may be sectioned into a larger number of regions, forexample, four or more regions.

Other configurations, operations, and effects may be the same as thosein the above-mentioned embodiments, and hence the detailed descriptionsthereof are herein omitted.

14. Fourteenth Embodiment

Next, a fourteenth embodiment is described in detail with reference tothe drawings.

In the above-mentioned embodiments, the case where the shielding film106 is used has been exemplified as the configuration for reducing theleakage of light that has entered a unit pixel 50 to a photodiode PD inan adjacent pixel 50. In the fourteenth embodiment, on the other hand, acase where a pillar array is used instead of the shielding film 106 isdescribed by way of example.

In the following description, the case based on the eighth embodiment isexemplified. The basic embodiment is not limited to the eighthembodiment, and may be another embodiment described above or describedbelow. In the following description, overlapping descriptions of thesame configurations, operations, and effects as the configurations,operations, and effects according to the above-mentioned embodiments areomitted by reference.

14.1 Cross-Sectional Structure Example of Unit Pixel

FIG. 57 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to the fourteenthembodiment. Similarly to FIG. 33 in the eighth embodiment, for example,FIG. 57 illustrates a cross-sectional structure example of thephotoreceiver chip 71 in FIG. 6, and omits a cross-sectional structureexample of the circuitry chip 72. In FIG. 57, wiring layers constitutingelectrical connection from the transfer transistor 51 and thephotoreceiver chip 71 to the circuitry chip 72 are also omitted. For thesake of description, FIG. 57 exemplifies a case where four unit pixels50B, 50R, 50G1, and 50G2 constituting a unit pattern 861 in Bayerarrangement are arranged in a row along the cross section.

As exemplified in FIG. 57, in a CMOS image sensor 10-14 according to thefourteenth embodiment, the unit pixels 50R, 50G1, 50G2, and 50B have aconfiguration obtained by, for example, omitting the pillars 110 fromthe unit pixel 50 exemplified above in the eighth embodiment withreference to FIG. 33 and replacing the shielding film 106 disposedbetween the unit pixels 50 with pillars 1410R, 1410G, or 1410B.

14.2 Planar Layout Example of Pillars

FIG. 58 is a diagram illustrating a plan layout example of the pillars1410 disposed in the color filters 107 in the unit pixels 50constituting a unit pattern of Bayer arrangement. As illustrated in FIG.58, in each unit pixel 50, for example, the pillars 1410 are arranged onthe insulator film 105 formed on the back surface side of thesemiconductor substrate 100 in at least two rows at a peripheral part ofeach color filter 107, thereby constituting a pillar array functioningas a spieling portion.

For example, at a peripheral part of a color filter 107R, the pillars1410R are disposed in two or more rows so as to surround a center partof the color filter 107R, thereby constituting a pillar array 1400R.Similarly, at a peripheral part of a color filter 107G, the pillars1410G are disposed in two or more rows so as to surround a center partof the color filter 107G, thereby constituting a pillar array 1400G. Ata peripheral part of a color filter 107B, the pillars 1410B are disposedin two or more rows so as to surround a center part of the color filter107B, thereby constituting a pillar array 1400B.

At the center part of each color filter 107, a pillar array for thepurpose of attenuating light leaking from an adjacent pixel 50 accordingto the above-mentioned embodiments may be provided

14.3 Spectroscopic Characteristics of Pillar Array

FIG. 59 is a diagram illustrating an example of spectroscopiccharacteristics of the pillar array 1400R provided in the unit pixel50R. As a reference, FIG. 59 also illustrates spectroscopiccharacteristics of the color filter 107R (light transmission spectrumSP107R).

As illustrated in FIG. 59, in the fourteenth embodiment, for example,the pillar array 1400R has at least one of a light transmission spectrumSP1410B selectively absorbing light having a wavelength component ofblue (B), a light transmission spectrum SP1410G selectively absorbinglight having a wavelength component of green (G), and a lighttransmission spectrum SP1410IR selectively absorbing light having awavelength component corresponding to IR light. In other words, thepillar array 1400R is configured by using the pillars 1410R that do notabsorb light having a wavelength component of red (R), and thusfunctions as a waveguide that transmits light having a wavelengthcomponent of red (R).

The above-mentioned configuration may be similarly applied to the otherpillar arrays 1400G and 1400B. In other words, the pillar array 1400G isconfigured by using the pillars 1410G that do not absorb light having awavelength component of green (G), and thus functions as a waveguidethat transmits light having a wavelength component of green (G). Thepillar array 1400B is configured by using the pillars 1410B that do notabsorb light having a wavelength component of blue (B), and thusfunctions as a waveguide that transmits light having a wavelengthcomponent of blue (B).

14.4 Function of Pillar as Optical Waveguide

FIG. 60 is a diagram for explaining propagation of light that hasobliquely entered a peripheral part of the color filter 107. In A, B,and C of FIG. 60, the description is given by referring to the colorfilter 107R, but the same may apply to the other color filters 107G and107B. In A, B, and C of FIG. 60, light L10 entering the color filter107R is, for example, light having a broad wavelength spectrum for avisible light region.

As illustrated in A, B, and C of FIG. 60, the light L10 that hasobliquely entered the peripheral part of the color filter 107Rpropagates through the color filter 107R, and, as illustrated in A ofFIG. 60, the wavelength spectrum thereof is shaped in accordance withspectroscopic characteristics (see light transmission spectrum SP107R inFIG. 59) of the color filter 107R. As a result, the light L10 isconverted into light L11 having a wavelength component of red. Afterthat, the light L11 enters the pillar 1410R located at the peripheralpart of the color filter 107R.

For example, the pillar 1410R has a refractive index lower than that ofthe surrounding color filter 107R. Thus, the light L11 that has enteredthe pillar 1410R is repeatedly reflected or totally reflected by aboundary surface of the pillar 1410R and the color filter 107R, and thenexits from the bottom surface of the pillar 1410R toward a photodiode PD(not shown). In this manner, the pillar 1410R functions as an opticalwaveguide that guides light, having entered the peripheral part of thecolor filter 107R, to the back surface (a surface on the side oppositeto a light incident surface) of the color filter 107R.

The light L11 that has entered the pillar 1410R propagates through thepillar 1410, and, as illustrated in B of FIG. 60, the wavelengthspectrum thereof is shaped in accordance with spectroscopiccharacteristics (see light transmission spectra SP1410R, SP1410G, andSP1401B in FIG. 59) of the pillar array 1400R. As a result, the lightL11 is converted into light L12 having a wavelength spectrum illustratedin C of FIG. 60. After that, the light L12 exits from the bottom surfaceof the pillar 1410R, that is, the back surface of the color filter 107R,toward the photodiode PD.

The above-mentioned configuration may be similarly applied to the othercolor filters 107G and 107B.

14.5 Actions and Effects

As described above, in the fourteenth embodiment, at the peripheral partof each color filter 107, the pillar array 1400 functioning as not onlya spieling portion that blocks light having wavelength components otherthan a wavelength component to be transmitted through the color filter107 but also an optical waveguide that guides light having thewavelength component to be transmitted through the color filter 107 tothe back surface of the color filter 107 is provided. Consequently, oflight that has obliquely entered the peripheral part of each colorfilter 107, light having wavelength components other than a wavelengthcomponent to be transmitted through the color filter 107 can beattenuated, and the exit of light having the wavelength component to betransmitted through the color filter 107 toward an adjacent pixel 50 canbe suppressed. As a result, the leakage of light that has obliquelyentered a unit pixel 50 to a photodiode PD in an adjacent pixel 50 canbe suppressed to improve the color reproducibility of acquired colorimages.

Other configurations, operations, and effects may be the same as thosein the above-mentioned embodiments, and hence the detailed descriptionsthereof are herein omitted.

15. Fifteenth Embodiment

In the above-mentioned embodiments, the case where the spectroscopiccharacteristics of the pillar array 1400 provided instead of theshielding film 106 are spectroscopic characteristics that light having awavelength component to be transmitted through a color filter 107 inwhich the pillar array 1400 is provided is transmitted and light havingother wavelength components is absorbed has been exemplified. However,the spectroscopic characteristics of the pillar array provided insteadof the shielding film 106 are not limited to such spectroscopiccharacteristics, and may be, for example, spectroscopic characteristicsof broad light absorption characteristics (light absorption spectrum)capable of absorbing at least a visible light region (may include IRlight region) as a whole.

FIG. 61 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to a fifteenthembodiment. Similarly to FIG. 57 in the fourteenth embodiment, forexample, FIG. 61 illustrates a cross-sectional structure example of thephotoreceiver chip 71 in FIG. 6, and omits a cross-sectional structureexample of the circuitry chip 72. In FIG. 61, wiring layers constitutingelectrical connection from the transfer transistor 51 and thephotoreceiver chip 71 to the circuitry chip 72 are also omitted. For thesake of description, FIG. 61 exemplifies a case where four unit pixels50B, 50R, 50G1, and 50G2 constituting a unit pattern 861 in Bayerarrangement are arranged in a row along the cross section.

As exemplified in FIG. 61, a CMOS image sensor 10-15 according to thefifteenth embodiment has a configuration obtained by replacing thepillars 1410R, 1410G, and 1410B provided at the peripheral part of thecolor filter 107 with pillars 1510R, 1510G, and 1510B, respectively, inthe same configuration as in the CMOS image sensor 10-14 described abovein the fourteenth embodiment with reference to FIG. 57.

As exemplified in FIG. 62, a plurality of pillars 1510 include aplurality of kinds of pillars 1510 having randomly different diameters,and the pillars 1510 are randomly disposed to constitute a pillar array1500 having broad light absorption characteristics (light absorptionspectrum) capable of absorbing at least a visible light region (mayinclude a region of IR light) as a whole.

By disposing the pillar array 1500 formed from the pillars 1510 havingthe configuration described above at a peripheral part of the colorfilter 107 instead of the shielding film 106, light that has obliquelyentered the peripheral part of the color filter 107 can be attenuated asa whole. As a result, the leakage of light that has obliquely entered aunit pixel 50 to a photodiode PD in an adjacent pixel 50 can besuppressed to improve the color reproducibility of acquired colorimages.

Other configurations, operations, and effects may be the same as thosein the above-mentioned embodiments, and hence the detailed descriptionsthereof are herein omitted.

16. Sixteenth Embodiment

In the above-mentioned embodiments, the case where the height of thepillars (such as the pillar 110) from the top surface of the insulatorfilm 105 is lower than the height of the color filter 107 from the topsurface of the insulator film 105, in other words, the case where thepillars are buried in the color filter 107, has been exemplified.However, the embodiments are not limited to such a configuration.

For example, as in a CMOS image sensor 10-16 exemplified in FIG. 63, theheight of a pillar 1610 from the top surface of the insulator film 105may be higher than the height of the color filter 107 from the topsurface of the insulator film 105. FIG. 63 exemplifies a case based onthe fourteenth embodiment, but the basic embodiment is not limited tothe fourteenth embodiment, and may be another embodiment described aboveor described later.

17. Seventeenth Embodiment

In the above-mentioned embodiments, the case where an FFTI pixelseparation portion is provided between unit pixels 50 has beenexemplified. The pixel separation portion is not limited to the FFTItype, and, for example, may be of an RDTI type as in a CMOS image sensor10-17 exemplified in FIG. 64. FIG. 64 exemplifies a case based on thefourteenth embodiment, but the basic embodiment is not limited to thefourteenth embodiment, and may be another embodiment described above ordescribed later.

18. Eighteenth Embodiment

Pupil correction can be applied to the above-mentioned embodiments. Inthis case, as in a CMOS image sensor 10-18 exemplified in FIG. 65 and aplan layout example of color filters 107 and photodiodes PD exemplifiedin FIG. 66, the positional relation between each color filter 107 andthe photodiode PD in addition to the positional relation between theon-chip lens 108 and the color filter 107 may be corrected (pupilcorrection).

In this case, similarly to the shift amount (correction amount) of theon-chip lens 108 with respect to the color filter 107, for example, theshift amount (correction amount) of the color filter 107 with respect tothe photodiode PD can be calculated based on the image height of theunit pixel 50 or chief ray angle (CRA) characteristics of the imaginglens (see FIG. 2).

FIG. 65 illustrates a cross-sectional structure example of a CMOS imagesensor 10-18 when an optical axis of the imaging lens 20 (for example,corresponding to the center in the effective pixel region of the pixelarray 11) is present in the right direction in the figure. FIG. 66 is aplan layout diagram of the color filters 107 and the photodiodes PD asseen from the light incident direction, illustrating an example of thepositional relation between the color filter 107 and the photodiode PDwhen the optical axis of the imaging lens 20 is present in the upperright direction in the figure.

FIG. 65 and FIG. 66 exemplify a case based on the fourteenth embodiment,but the basic embodiment is not limited to the fourteenth embodiment,and may be another embodiment described above or described later.

19. Nineteenth Embodiment

Next, a nineteenth embodiment is described in detail with reference tothe drawings.

As exemplified in FIG. 67, in a general CMOS image sensor, a region(hereinafter referred to “shielding region”) 9002 around an effectivepixel region 9001 in a pixel array is covered with a shielding film(hereinafter referred to as “optical black (OPB) solid film”) 916 thatblocks light entering a peripheral part of the pixel array.

On the OPB solid film 916, a color filter 907 is formed continuouslyfrom the effective pixel region 9001 in order to maintain themanufacturing precision (such as precision of shape) of the color filter907 at the peripheral part of the effective pixel region 9001.

On the color filter 907 in the shielding region 9002, a film(hereinafter referred to as “anti-flare film”) 926 having a broad lightabsorption spectrum for at least a visible light region is provided inorder to reduce the generation of flare caused by diffused reflection oflight entering the shielding region 9002.

At at least a boundary part between the effective pixel region 9001 andthe shielding region 9002 on the anti-flare film 926, an on-chip lens918 formed continuously from the on-chip lens 908 in the effective pixelregion 9001 is provided in order to maintain the manufacturing precision(such as precision of shape) of the on-chip lens 908 at the peripheralpart of the effective pixel region 9001.

In the case of the configuration described above, the surface, in theshielding region 9002, on which the on-chip lens 918 is formed (forexample, the top surface of the anti-flare film 926) becomes higher thanthe surface, in the effective pixel region 9001, on which the on-chiplens 908 is formed (for example, the top surface of the color filter907) by a thickness h0 determined by adding the thickness of the OPBsolid film 916 and the thickness of the anti-flare film 926, and a stephaving the thickness h0 is formed at the boundary part between theeffective pixel region 9001 and the shielding region 9002.

When such a step occurs, it is difficult to maintain the manufacturingprecision (such as precision of shape) of the on-chip lens 908 at theperipheral part in the effective pixel region 9001. Accordingly, it isdifficult to acquire accurate color information (pixel signal) of lightthat has entered a unit pixel located at the peripheral part of theeffective pixel region 9001, and a unit pixel that should besubstantially ineffective comes into existence at the peripheral part ofthe effective pixel region 9001. Thus, there is a problem in that theeffective pixel region is reduced.

In view of the above, in the nineteenth embodiment, by reducing a stepof the surface on which the on-chip lens is formed at a boundary partbetween the effective pixel region and the shielding region, themanufacturing precision of the on-chip lens formed at the peripheralpart of the effective pixel region can be maintained to reduce thereduction of the effective pixel region.

In the following description, the case based on the eighth embodiment isexemplified. The basic embodiment is not limited to the eighthembodiment, and may be another embodiment described above or describedbelow. In the following description, overlapping descriptions of thesame configurations, operations, and effects as the configurations,operations, and effects according to the above-mentioned embodiments areomitted by reference.

19.1 Plan Layout of Photoreceiver Chip

FIG. 68 is a diagram illustrating a plan layout example of thephotoreceiver chip according to the nineteenth embodiment. Asillustrated in FIG. 68, the pixel array 11 (see FIG. 3) formed in thephotoreceiver chip 71 is divided into an effective pixel region 1901 anda shielding region 1902. For example, the effective pixel region 1901may be a region in which unit pixels 50 that are targets from whichpixel signals constituting image data are read are arranged in atwo-dimensional grid pattern. For example, the shielding region 1902 maybe a region in which unit pixels 50 are arranged but the light incidentsurfaces of the photodiodes PD are covered with an OPB solid film 1916described later.

In the shielding region 1902, a pillar array 1900 configured by aplurality of pillars 1910 arranged with a pitch shorter than the pitchof the photodiodes PD in the effective pixel region 1901 is provided.For example, the pillar array 1900 functions as a substitute of ananti-flare film that reduces the generation of flare caused by diffusedreflection of light entering the shielding region 1902. In view of theabove, in the nineteenth embodiment, the pillar array 1900 is configuredto have a broad light absorption spectrum for at least a visible lightregion.

For example, the pillar array 1900 having such a light absorptionspectrum can be configured by a plurality of kinds of pillars 1910 thediameters and pitches of which are (randomly) different, as with thepillar arrays configured by the pillars 211 and 212 described above inthe second embodiment with reference to FIG. 21. Alternatively, thepillar array 1900 may be configured by pillars 1910 the diameters ofwhich change gradually or step by step from the bottom surface(insulator film 105 side) toward the top surface or the apex as with thepillars 310 described above in the third embodiment with reference toFIG. 22. However, the pillar array is not limited thereto, and may bevariously modified as long as the pillar array has a broad lightabsorption spectrum for at least a visible light region.

19.2 Cross-Sectional Structure Example of Shielding Region

FIG. 69 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to the nineteenthembodiment. For simple description, FIG. 69 illustrates across-sectional structure example of layers upper than the insulatorfilm 105 in the above-mentioned embodiments, and omits cross-sectionalstructures of lower layers. For example, the cross-sectional structuresof the layers lower than the insulator film 105 in the effective pixelregion 1901 may be the same as in the above-mentioned embodiments (see,for example, FIG. 33). In the shielding region 1902, the vicinity of aboundary with the effective pixel region 1901 may be the same as in theabove-mentioned embodiments, and in a region apart from the boundarywith the effective pixel region 1901, the photodiode PD (for example,N-type semiconductor region 101) may be omitted.

As in a CMOS image sensor 10-19 exemplified in FIG. 69, in the shieldingregion 1902, the top surface of the insulator film 105 formed on theback surface side of the semiconductor substrate 100 is covered with anOPB solid film 1916. For the OPB solid film 1916, for example, materialsuch as tungsten (W) can be used similarly to the shielding film 106 inthe above-mentioned embodiments.

On the OPB solid film 1916, a pillar array 1900 configured by aplurality of pillars 1910 is provide.

Furthermore, on the OPB solid film 1916 on which the pillar array 1900is provided, an on-chip lens 1918 formed continuously from the on-chiplens 108 in the effective pixel region 1901 is provided.

19.3 Diameter, Pitch, and Height of Pillars

For example, a plurality of diameters of the pillars 1910 can be set inthe range of 80 to 130 nm regularly or randomly.

For example, a plurality of pitches between the pillars 1910 can be setin the range of 200 to 480 nm regularly or randomly.

Furthermore, for example, the height of the pillars 1910 can be set toabout 300 nm.

However, the diameter, the pitch, and the height of the pillars 1910according to the nineteenth embodiment are not limited to theabove-mentioned numerals, and can be variously changed as long as thepillar array has a board light absorption spectrum for at least avisible light region.

19.4 Actions and Effects

As described above, in the nineteenth embodiment, the pillar array 1900buried in the on-chip lens 1918 is provided instead of an anti-flarefilm. In this manner, a step between the surface in the effective pixelregion 1901 on which the on-chip lens 108 is formed and the surface inthe shielding region 1902 on which the on-chip lens 1918 is formed canbe reduced by the height of the anti-flare film, and hence themanufacturing precision (such as precision of shape) of the on-chip lens108 at the peripheral part of the effective pixel region 1901 can bemaintained.

In the nineteenth embodiment, the pillar array 1900 is configured tohave a broad light absorption spectrum for at least a visible lightregion, and hence the color filter 107 in the shielding region 1902 canbe omitted. Consequently, the step between the surface in the effectivepixel region 1901 on which the on-chip lens 108 is formed and thesurface in the shielding region 1902 on which the on-chip lens 1918 isformed can be further reduced to further reduce a difference h1 betweenthe height of the on-chip lens 108 in the effective pixel region 1901and the height of the on-chip lens 1918 in the shielding region 1902after the manufacturing. Thus, the manufacturing precision (such asprecision of shape) of the on-chip lens 108 at the peripheral part ofthe effective pixel region 1901 can be further maintained.

Other configurations, operations, and effects may be the same as thosein the above-mentioned embodiments, and hence the detailed descriptionsthereof are herein omitted.

20. Twentieth Embodiment

In the above-mentioned nineteenth embodiment, the color filter 107 inthe shielding region 1902 is omitted to further reduce the step betweenthe formation surface of the on-chip lens 108 in the effective pixelregion 1901 and the formation surface of the on-chip lens 1918 in theshielding region 1902. However, the color filter 107 in the shieldingregion 1902 is not necessarily required to be omitted.

In this case, for example, as in a CMOS image sensor 10-20 exemplifiedin FIG. 70, a pillar 2010 is formed on the OPB solid film 1916 and inthe color filter 107.

As exemplified in FIG. 71, spectroscopic characteristics of a pillararray configured by pillars 2010R formed in a color filter 107R in theshielding region 1902 may be spectroscopic characteristics that absorblight having a wavelength region R_R mainly transmitted through at leastthe color filter 107R (light transmission spectrum SP107R). In thismanner, a combined filter having a broad light absorption spectrum in atleast a visible light region is formed by the color filter 107R and thepillar array configured by the pillars 2010R, and hence the generationof flare caused by light entering the color filter 107R in the shieldingregion 1902 can be suppressed.

Similarly, spectroscopic characteristics of a pillar array configured bypillars 2010G formed in a color filter 107G in the shielding region 1902may be spectroscopic characteristics that absorb light having awavelength region R_G (see FIG. 71) mainly transmitted through at leastthe color filter 107G (light transmission spectrum SP107G). In thismanner, a combined filter having a broad light absorption spectrum in atleast a visible light region is formed by the color filter 107G and thepillar array configured by the pillars 2010G, and hence the generationof flare caused by light entering the color filter 107G in the shieldingregion 1902 can be suppressed.

In FIG. 70, the color filter 107B is not provided in the shieldingregion 1902. Without being limited thereto, the color filter 107B may beprovided in the shielding region 1902. In this case, spectroscopiccharacteristics of a pillar array configured by pillars 2010B formed inthe color filter 107B in the shielding region 1902 may be spectroscopiccharacteristics that absorb light in a wavelength region R_B (see FIG.71) mainly transmitted through at least the color filter 107B (lighttransmission spectrum SP107B). In this manner, a combined filter havinga broad light absorption spectrum in at least a visible light region isformed by the color filter 107B and the pillar array configured by thepillars 2010B, and hence the generation of flare caused by lightentering the color filter 107B in the shielding region 1902 can besuppressed.

For example, the diameter of the pillars 2010R formed in the colorfilter 107R in the shielding region 1902 can be set in the range of 80to 120 nm. For example, the pitch between the pillars 2010R can be setto 400 nm. For example, the height of the pillars 2010R can be set to300 nm.

For example, the diameter of the pillars 2010G formed in the colorfilter 107G in the shielding region 1902 can be set in the range of 80to 130 nm. For example, the pitch between the pillars 2010R can be setto 320 nm. For example, the height of the pillars 2010R can be set to300 nm.

In the case where the color filter 107B is provided in the shieldingregion 1902, for example, the diameter of the pillars 2010B formed inthe color filter 107B in the shielding region 1902 can be set in therange of 60 to 80 nm. For example, the pitch between the pillars 2010Bcan be set to 280 nm. For example, the height of the pillars 2010B canbe set to 300 nm. For example, similarly to the pillars constituting thepillar array 800G described above in the eighth embodiment withreference to FIG. 36, the pillar 2010G may have a structure in which thepillar 2010R and the pillar 2010B are stacked.

These numerals and structures are merely examples, and may be variouslymodified depending on the material used for the pillar 2010.

As described above, the combined filter configured by the color filter107 and the pillar array can be used instead of an anti-flare film.Consequently, a step h2 between the surface, in the effective pixelregion 1901, on which the on-chip lens 108 is formed and the surface, inthe shielding region 1902, on which the on-chip lens 1918 is formed canbe reduced by the height of the anti-flare film, and hence themanufacturing precision (such as precision of shape) of the on-chip lens108 at the peripheral part of the effective pixel region 1901 can bemaintained.

Other configurations, operations, and effects may be the same as thosein the above-mentioned embodiments, and hence the detailed descriptionsthereof are herein omitted.

21. Twenty-First Embodiment

Next, a twenty-first embodiment is described in detail with reference tothe drawings.

In the above-mentioned nineteenth embodiment, by providing the pillararray 1900 having a broad light absorption spectrum for at least avisible light region instead of an anti-flare film, the generation offlare caused by diffused reflection of light entering the shieldingregion 1902 is suppressed.

In the twenty-first embodiment, on the other hand, a case where a pillararray in addition to the anti-flare film is provided in the shieldingregion so as to further suppress the generation of flare caused bydiffused reflection of light entering the shielding region is describedby way of example.

In the above-mentioned embodiments, the CMOS image sensor 10 capable ofacquiring a color image, which includes the color filter 107 in at leastthe effective pixel region, has been exemplified. The basic image sensoris not limited to an image sensor that acquires color images. Forexample, an image sensor that generates monochrome pixel signals for thepurpose of ranging and sensing can be intended. In view of the above, inthe twenty-first embodiment, a case based on an image sensor thatgenerates monochrome pixel signals is taken as an example.

21.1 Cross-Sectional Structure Example of Shielding Region

FIG. 72 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to the twenty-firstembodiment. For simple description, FIG. 72 illustrates across-sectional structure example of layers upper than the insulatorfilm 105 in the above-mentioned embodiments, and omits thecross-sectional structure of lower layers. However, for example, thecross-sectional structures of the layers lower than the insulator film105 in an effective pixel region 2101 may be the same as in theabove-mentioned embodiments (see, for example, FIG. 33). In a shieldingregion 2102, the vicinity of a boundary with the effective pixel region2101 may be the same as in the above-mentioned embodiments, and in aregion apart from the boundary with the effective pixel region 2101, thephotodiode PD (for example, N-type semiconductor region 101) may beomitted.

As illustrated in FIG. 72, in the effective pixel region 2101 in theCMOS image sensor 10-21, for example, on-chip lenses 2108 havingrectangular cross sections are provided on the top surface of theinsulator film 105 formed on the back surface side of the semiconductorsubstrate 100. The shapes of the top surface and the bottom surface ofeach on-chip lens 2108 may be various shapes such as a circle, an oval,and polygons of a triangle or larger. Instead of the on-chip lens 2108having a rectangular cross section, the on-chip lens 108 the top surfaceof which has a radius of curvature as exemplified in the above-mentionedembodiments may be used.

A shielding film 106 that reduces the leakage of light, having obliquelyentered a unit pixel 50, to a photodiode PD in an adjacent pixel 50 isprovided between the on-chip lenses 2108.

In the shielding region 2102, on the other hand, an OPB solid film 2116is formed on the top surface of the insulator film 105. For example, theformation region of the OPB solid film 2116 may be the entire shieldingregion 2102, or may be a region from a position apart from a boundarybetween the effective pixel region 2101 and the shielding region 2102 bya predetermined distance (for example, one unit pixel 50) to the outeredge of the shielding region 2102.

FIG. 72 exemplifies the structure in which the insulator film 105 onwhich the shielding film 106 and the OPB solid film 2116 are formed iscovered by a passivation film 2109, but the passivation film 2109 may beomitted, or may be formed so as to cover the surfaces of the on-chiplenses 2108 and 2118. In the following description, it is assumed thatthe passivation film 2109 is omitted for clarity.

A pillar array 2100 configured by a plurality of pillars 2110 isprovided on the top surface of the OPB solid film 2116. For example,similarly to the pillar array 1900 exemplified in the nineteenthembodiment, the pillar array 2100 may be designed to have a broad lightabsorption spectrum in at least a visible light region.

On the surface of the OPB solid film 2116 on which the pillars 2110 areprovided, an anti-flare film 2126 is provided such that the pillars 2110are buried.

The surface of the anti-flare film 2126 is covered with an on-chip lens2118 formed continuously from the on-chip lens 2108 in the effectivepixel region 2101 in order to maintain the manufacturing precision (suchas precision of shape) of the on-chip lens 2108 at the peripheral partof the effective pixel region 2101.

Other configurations may be the same as those in the nineteenthembodiment, for example, and hence the detailed descriptions thereof areherein omitted.

21.2 Actions and Effects

As described above, by using the anti-flare film 2126 and the pillararray 2100 in combination and burying the pillar array 2100 in theanti-flare film 2126, the thickness of the anti-flare film 2126 can bereduced without deteriorating the flare reduction ability. Consequently,the step between the surface in the effective pixel region 2101 on whichthe on-chip lens 2108 is formed and the surface in the shielding region2102 on which the on-chip lens 2118 is formed can be reduced by thereduced thickness, and hence the manufacturing precision (such asprecision of shape) of the on-chip lens 2108 at the peripheral part ofthe effective pixel region 2101 can be maintained.

Other configurations, operations, and effects may be the same as thosein the above-mentioned embodiments, and hence the detailed descriptionsthereof are herein omitted.

22. Twenty-Second Embodiment

Although, in the twenty-first embodiment, the case where the pillararray 2100 and the anti-flare film 2126 are formed on the OPB solid film2116 has been exemplified, the present invention is not limited to sucha configuration. For example, the OPB solid film 2116 may be omitted asin a CMOS image sensor 10-22 exemplified in FIG. 73.

In this manner, by omitting the OPB solid film 2116, a step between asurface, in the effective pixel region 2101, on which the on-chip lens2108 is formed and a surface, in the shielding region 2102, on which theon-chip lens 2118 is formed can be reduced by the thickness of the OPBsolid film 2116. Thus, the manufacturing precision (such as precision ofshape) of the on-chip lens 108 at the peripheral part of the effectivepixel region 1901 can be further maintained.

Other configurations, operations, and effects may be the same as thosein the above-mentioned embodiments, and hence the detailed descriptionsthereof are herein omitted.

23. Twenty-Third Embodiment

Although, in the above-mentioned twenty-second embodiment, the casewhere the OPB solid film 2116 is omitted has been exemplified, thepresent invention is not limited to such a configuration. For example,the anti-flare film 2126 may be further omitted as in a CMOS imagesensor 10-23 exemplified in FIG. 74.

In this manner, by omitting the anti-flare film 2126, the step betweenthe surface in the effective pixel region 2101 on which the on-chip lens2108 is formed and the surface in the shielding region 2102 on which theon-chip lens 2118 is formed can be reduced by a difference between theheight of the anti-flare film 2126 and the height of the pillar 2110,and hence the manufacturing precision (such as precision of shape) ofthe on-chip lens 108 at the peripheral part of the effective pixelregion 1901 can be further maintained.

Other configurations, operations, and effects may be the same as thosein the above-mentioned embodiments, and hence the detailed descriptionsthereof are herein omitted.

24. Twenty-Fourth Embodiment

In the above-mentioned nineteenth to twenty-third embodiments, the casewhere the pillar 1910, 2010, or 2110 is provided in the shielding region1902 or 2102 has been exemplified. The location to dispose the pillar1910, 2010, or 2110 is not limited to the shielding region 1902 or 2102.For example, as illustrated in FIG. 75, the pillar 1910, 2010, or 2110may be provided on the shielding film 106 provided at a boundary part ofunit pixels 50. The shielding film 106 may be omitted from theconfiguration illustrated in FIG. 75.

Such a configuration can decrease the thickness of the shielding film106 or omit the shielding film 106.

FIG. 75 illustrates a case based on the twenty-first embodiment, but thebasic embodiment is not limited to the twenty-first embodiment, and maybe another embodiment described above or described later.

Other configurations, operations, and effects may be the same as thosein the above-mentioned embodiments, and hence the detailed descriptionsthereof are herein omitted.

25. Twenty-Fifth Embodiment

Next, a twenty-first embodiment is described in detail with reference tothe drawings.

In the above-mentioned first to eighteenth embodiments, the case wherethe pillars are disposed in the color filter 107 has been exemplified.The arrangement location of the pillars is not limited to the inside ofthe color filter 107, and can be variously changed. In the twenty-fifthembodiment, a case where pillars are disposed in an on-chip lens isdescribed by way of example.

25.1 Cross-Sectional Structure Example of Unit Pixel

FIG. 76 is a cross-sectional diagram illustrating a cross-sectionalstructure example of a CMOS image sensor according to the twenty-fifthembodiment. Similarly to FIG. 33 in the eighth embodiment, for example,FIG. 76 illustrates a cross-sectional structure example of thephotoreceiver chip 71 in FIG. 6, and omits a cross-sectional structureexample of the circuitry chip 72. In FIG. 76, wiring layers constitutingelectrical connection from the transfer transistor 51 and thephotoreceiver chip 71 to the circuitry chip 72 are also omitted. For thesake of description, FIG. 76 exemplifies a case where three unit pixels50R, 50G, and 50B that receive wavelength components of three primarycolors of RGB are arranged in a row along the cross section.

As exemplified in FIG. 76, a CMOS image sensor 10-25 according to thetwenty-fifth embodiment has, for example, the same cross-sectionalstructure as the CMOS image sensor 10-18 according to the eighthembodiment exemplified in FIG. 33 but the color filter 107 is omitted,the pillars 110 are replaced by pillars 2510, and the pillars 2510 aredisposed in an on-chip lens 2508.

In other words, the CMOS image sensor 10-25 according to thetwenty-fifth embodiment has a configuration in which the on-chip lens2508 including the pillars 2510 inside is provided on the top surface ofthe insulator film 105 formed on the back surface side of thesemiconductor substrate 100.

FIG. 76 exemplifies the on-chip lenses 2508 separated for each unitpixel 50. Without being limited thereto, for example, the on-chip lenses2508 may be integrally formed so as to be continuous across adjacentpixels 50 like the on-chip lenses 108 exemplified in the eighthembodiment. In FIG. 76, the passivation film 109 is omitted, but thepassivation film 109 may be provided.

To more specifically describe the configuration illustrated in FIG. 76,a pillar array configured by a plurality of pillars 2510R is provided inan on-chip lens 2508R in a unit pixel 50R that generates a pixel signalbased on light having a wavelength component corresponding to red. Forexample, similarly to the pillar array 1400R exemplified in thefourteenth embodiment, the pillar array configured by the pillars 2510Rhas a light transmission spectrum SP1410B selectively absorbing lighthaving a wavelength component of blue (B), a light transmission spectrumSP1410G selectively absorbing light having a wavelength component ofgreen (G), and a light transmission spectrum SP1410IR selectivelyabsorbing light having a wavelength component corresponding to IR light(see, for example, FIG. 59). In other words, the pillar array configuredby the pillars 2510R has spectroscopic characteristics that transmitlight having a wavelength component of red (R) and absorb light havingother wavelength components.

Similarly, a pillar array configured by a plurality of pillars 2510G isprovided in an on-chip lens 2508G in a unit pixel 50G that generates apixel signal based on light having a wavelength component correspondingto green. For example, similarly to the pillar array 1400G exemplifiedin the fourteenth embodiment, the pillar array configured by the pillars2510G has a light transmission spectrum SP1410B selectively absorbinglight having a wavelength component of blue (B), a light transmissionspectrum SP1410R selectively absorbing light having a wavelengthcomponent of red (R), and a light transmission spectrum SP1410IRselectively absorbing light having a wavelength component correspondingto IR light (see, for example, FIG. 59). In other words, the pillararray configured by the pillars 2510G has spectroscopic characteristicsthat transmit light having a wavelength component of green (G) andabsorb light having other wavelength components.

Similarly, a pillar array configured by a plurality of pillars 2510B isprovided in an on-chip lens 2508B in a unit pixel 50B that generates apixel signal based on light having a wavelength component correspondingto blue. For example, similarly to the pillar array 1400B exemplified inthe fourteenth embodiment, the pillar array configured by the pillars2510B has a light transmission spectrum SP1410G selectively absorbinglight having a wavelength component of green (G), a light transmissionspectrum SP1410R selectively absorbing light having a wavelengthcomponent of red (R), and a light transmission spectrum SP1410IRselectively absorbing light having a wavelength component correspondingto IR light (see, for example, FIG. 59). In other words, the pillararray configured by the pillars 2510B has spectroscopic characteristicsthat transmit light having a wavelength component of blue (B) and absorblight having other wavelength components.

However, in the twenty-fifth embodiment, the pillars 2510R are providedat at least a center part of the on-chip lens 2508R. Otherconfigurations may be the same as, for example, the cross-sectionalstructure example of the unit pixel 50 described above in the eighthembodiment with reference to FIG. 33.

25.2 Manufacturing Method for On-Chip Lens

Next, a manufacturing method for an on-chip lens including pillarstherein according to the twenty-fifth embodiment is described below byway of specific example. In the following description, the insulatorfilm 105 has already been formed on the back surface side of thesemiconductor substrate 100, and the shielding film 106 has already beenformed on the insulator film 105.

In this manufacturing method, first, as illustrated in FIG. 77, pillars2510A made of the same material as the pillars 2510 are formed on theinsulator film 105 formed on the back surface side of the semiconductorsubstrate 100. The material of the pillar 2510A and its crystal statemay be the same as in the above-mentioned embodiments. For the formationof the pillar 2510A, for example, photolithography and etchingtechnology can be used. Specifically, for example, a material film ofthe same material as the pillar 2510 is formed on the insulator film105, and a resist solution is spin-coated on the top surface of thematerial film. An arrangement pattern of the pillars 2510 is transferredto the spin-coated resist solution to form a resist film having the samepattern as the arrangement pattern of the pillars 2510. The materialfilm is etched by, for example, DRIE with the use of the resist film asa mask to form the pillars 2510A. For example, the height of themanufactured pillar 2510A may be equal to or higher than the height ofthe highest pillar 2510 among the pillars 2510 after the processing.

Next, as illustrated in FIG. 78, on the insulator film 105 on which thepillars 2510A are formed, a material film 2508A of the same material asthe on-chip lens 2508 is formed such that the pillars 2510A are buried.For the material of the material film 2508A, for example, silicon oxide(SiO₂) can be used. For the formation of the material film 2508A, forexample, sputtering or CVD (including plasma CVD) can be used.

Next, as illustrated in FIG. 79, the top surface of the material film2508A is planarized by, for example, chemical mechanical polishing(CMP). In this case, the top surface of the pillar 2510A may be exposedfrom the top surface of the material film 2508A.

Next, as illustrated in FIG. 80, a resist film R25 for each unit pixel50 is formed on the top surface of the material film 2508A. For example,the formation position of the resist film R25 may be a center part in aregion in which each unit pixel 50 is formed. For the formation of theresist film R25, ordinary photolithography may be used.

Next, the resist film R25 on the material film 2508A is heated andmolten so that, as illustrated in FIG. 81, the surface of the softenedresist film R25 has a radius of curvature. For the heating of the resistfilm R25, baking and annealing can be used.

Next, the resist film R25, the material film 2508A, and the pillars2510A are etched from above the resist film R25 a surface of which has aradius of curvature, thereby transferring the radius of curvature of thesurface of the resist film R25 to the surface of a structure of thematerial film 2508A and the pillars 2510A. In this manner, asillustrated in FIG. 82, the on-chip lens 2508 including the pillars 2510inside is formed. In the etching in this case, it is preferred to useetching conditions that the selection ratios for the resist film R25,the material film 2508A, and the pillars 2510A are the same. However,the radius of curvature of the surface of the resist film R25 is notrequired to be transferred to the material film 2508A and the pillars2510A as it is. The radius of curvature of the surface of the resistfilm R25 may be different from the radius of curvature of the surface ofthe on-chip lens 2508 after the processing.

25.3 Actions and Effects

As described above, by disposing the pillar array configured by thepillars 2510 functioning as a wavelength filter in the on-chip lens2508, the color filter 107 can be omitted. Consequently, the thicknessof the photoreceiver chip 71 can be decreased, and an electronic devicecan be downsized due to the downsized CMOS image sensor 10-25.

Other configurations, operations, and effects may be the same as thosein the above-mentioned embodiments, and hence the detailed descriptionsthereof are herein omitted.

26. Twenty-Sixth Embodiment

In the above-mentioned twenty-fifth embodiment, the diameters and thepitches of the pillars 2510 provided in each on-chip lens 2508 can bevariously changed similarly to the above-mentioned embodiments.

For example, as in a CMOS image sensor 10-26 exemplified in FIG. 83, thediameters and the pitches of pillars 2610 provided in each on-chip lens2608 can be randomly changed (see, for example, FIG. 21) so as toconstitute a pillar array as a wavelength filter for broadly absorbinglight in a visible light region as a whole, thereby constituting a unitpixel 501R that generates a pixel signal based on IR light.

The pillar array for broadly absorbing light in a visible light regionas a whole is not limited to the random configuration exemplified inFIG. 21, and can be implemented by various configurations as exemplifiedin FIG. 22 and FIG. 35 in which the diameter changes gradually or stepby step from the bottom surface (insulator film 105 side) toward the topsurface or the apex.

27. Twenty-Seventh Embodiment

The above-mentioned embodiments are not limited to the structure inwhich one on-chip lens 108 or 2508 is disposed in one unit pixel 50, andcan be similarly applied to a structure in which one on-chip lens isdisposed in two or more unit pixels 50.

For example, as in a CMOS image sensor 10-27 exemplified in FIG. 84, thestructure exemplified in the twenty-fifth embodiment can be similarlyapplied to a structure in which one on-chip lens 2708 is disposed in twounit pixels 50.

FIG. 84 exemplifies the case based on the twenty-fifth embodiment.However, the basic embodiment is not limited to the twenty-fifthembodiment, and may be the embodiments described above or describedlater.

28. Twenty-Eighth Embodiment

Furthermore, in the above-mentioned embodiments, the case where the unitpixels 50 are separated by the FFTI or RDTI pixel separation portion hasbeen exemplified. The above-mentioned embodiments are not limited tothese configurations.

For example, as in a CMOS image sensor 10-28 exemplified in FIG. 85, theunit pixels 50 are not necessarily required to be separated by a pixelseparation portion.

FIG. 85 exemplifies the case based on the twenty-fifth embodiment. Thebasic embodiment is not limited to the twenty-fifth embodiment, and maybe any one of the above-mentioned embodiments.

29. Applications to Mobile Body

The technology according to the present disclosure (present technology)may be applied to various products. For example, the technologyaccording to the present disclosure may be implemented as devicesmounted on any kind of mobile bodies, including automobiles, electricvehicles, hybrid electric vehicles, motorcycles, bicycles, personalmobilities, airplanes, drones, ships, and robots.

FIG. 86 is a block diagram illustrating a schematic configurationexample of a vehicle control system as an example of a mobile controlsystem to which the technology according to the present disclosure maybe applied.

A vehicle control system 12000 includes a plurality of electroniccontrol units connected through a communication network 12001. In theexample illustrated in FIG. 86, the vehicle control system 12000includes a driving system control unit 12010, a body system control unit12020, an outside-vehicle information detection unit 12030, anin-vehicle information detection unit 12040, and an integrated controlunit 12050. As a functional configuration of the integrated control unit12050, a microcomputer 12051, a voice and image output unit 12052, andan on-vehicle network interface (I/F) 12053 are illustrated.

The driving system control unit 12010 controls the operation of devicesrelated to a driving system of a vehicle in accordance with variouskinds of computer programs. For example, the driving system control unit12010 functions as a control device such as a drive power generationdevice configured to generate drive power for a vehicle, such as aninternal combustion engine and a drive motor, a drive power transmissionmechanism configured to transmit drive power to a wheel, a steeringmechanism configured to adjust a steering angle of a vehicle, and abraking device configured to generate braking force for a vehicle.

The body system control unit 12020 controls the operation of variouskinds of device mounted to the vehicle body in accordance with variouskinds of computer programs. For example, the body system control unit12020 functions as a control device for a keyless entry system, a smartkey system, a power window device, or various kinds of lamps such as ahead lamp, a back lamp, a brake lamp, a blinker, and a fog lamp. In thiscase, radio waves transmitted from a mobile terminal substituting for akey or signals from various kinds of switches may be input to the bodysystem control unit 12020. The body system control unit 12020 receivesinput of the radio waves or the signals to control a door lock device, apower window device, and a lamp of the vehicle.

The outside-vehicle information detection unit 12030 detects informationoutside a vehicle having the vehicle control system 12000 mountedthereon. For example, an imaging unit 12031 is connected to theoutside-vehicle information detection unit 12030. The outside-vehicleinformation detection unit 12030 causes the imaging unit 12031 to takean image outside the vehicle, and receives the taken image. Based on thereceived image, the outside-vehicle information detection unit 12030 mayperform object detection processing for persons, cars, obstacles, signs,or characters on a road surface or perform distance detectionprocessing.

The imaging unit 12031 is an optical sensor configured to receive lightand outputting an electric signal corresponding to the received lightamount. The imaging unit 12031 may output the electric signal as animage, and may output the electric signal as ranging information. Lightreceived by the imaging unit 12031 may be visible light or invisiblelight such as infrared rays.

The in-vehicle information detection unit 12040 detects informationinside the vehicle. For example, a driver state detection unit 12041configured to detect the state of a driver is connected to thein-vehicle information detection unit 12040. For example, the driverstate detection unit 12041 includes a camera configured to taking animage of a driver, and the in-vehicle information detection unit 12040may calculate the degree of fatigue or degree of concentration of thedriver or determine whether the driver is asleep based on detectioninformation input from the driver state detection unit 12041.

The microcomputer 12051 can calculate a control target value for a drivepower generation device, a steering mechanism, or a braking device basedon information inside or outside the vehicle acquired by theoutside-vehicle information detection unit 12030 or the in-vehicleinformation detection unit 12040, and output a control instruction tothe driving system control unit 12010. For example, the microcomputer12051 can perform collaborative control for the purpose of implementingfunctions of an advanced driver assistance system (ADAS) includingvehicle collision avoidance or impact alleviation, tracking traveling,vehicle speed keeping traveling, and vehicle collision warning based oninter-vehicular distance, or vehicle lane deviation warning.

The microcomputer 12051 can perform collaborative control for thepurpose of automatic driving to autonomously drive independently ofdriver's operation by controlling the drive power generation device, thesteering mechanism, or the braking device based on information aroundthe vehicle acquired by the outside-vehicle information detection unit12030 or the in-vehicle information detection unit 12040.

The microcomputer 12051 can output a control instruction to the bodysystem control unit 12020 based on information outside the vehicleacquired by the outside-vehicle information detection unit 12030. Forexample, the microcomputer 12051 can perform collaborative control forthe purpose of antiglare to control a head lamp in accordance with theposition of a preceding vehicle or an oncoming vehicle detected by theoutside-vehicle information detection unit 12030 and switch from highbeams to low beams.

The voice and image output unit 12052 transmits an output signal of atleast one of voice and images to an output device capable of notifying avehicle occupant or the outside of the vehicle of information visuallyor aurally. FIG. 86 exemplifies an audio speaker 12061, a display unit12062, and an instrument panel 12063 as output devices. For example, thedisplay unit 12062 may include at least one of an onboard display and ahead-up display.

FIG. 87 is a diagram illustrating an example of an installation positionof the imaging unit 12031.

In FIG. 87, as the imaging unit 12031, imaging units 12101, 12102,12103, 12104, and 12105 are provided.

For example, the imaging units 12101, 12102, 12103, 12104, and 12105 areprovided at positions of a front nose, side mirrors, a rear bumper, anda back door of a vehicle 12100 and an upper part of a front window inthe vehicle interior. The imaging unit 12101 provided to the front noseand the imaging unit 12105 provided at the upper part of the frontwindow in the vehicle interior mainly acquire images in front of thevehicle 12100. The imaging units 12102 and 12103 provided to the sidemirrors mainly acquire images on the sides of the vehicle 12100. Theimaging unit 12104 provided to the rear bumper or the back door mainlyacquires images behind the vehicle 12100. The imaging unit 12105provided at the upper part of the front window in the vehicle interioris mainly used for detection of preceding vehicles, pedestrians,obstacles, traffic lights, road signs, or lanes.

FIG. 87 illustrates an example of photographing ranges of the imagingunits 12101 to 12104. An imaging range 12111 indicates an imaging rangeof the imaging unit 12101 provided to the front nose. Imaging ranges12112 and 12113 indicate imaging ranges of the imaging units 12102 and12103 provided to the side mirrors, respectively. An imaging range 12114indicates an imaging range of the imaging unit 12104 provided to therear bumper or the back door. For example, pieces of image data taken bythe imaging units 12101 to 12104 are superimposed to obtain an overheadimage seen from above the vehicle 12100.

At least one of the imaging units 12101 to 12104 may have a function foracquiring distance information. For example, at least one of the imagingunits 12101 to 12104 may be a stereo camera including a plurality ofimaging elements, or may be an imaging element having pixels for phasedifference detection.

For example, the microcomputer 12051 can determine a distance to eachthree-dimensional object in the imaging ranges 12111 to 12114 and atemporal change of the distance (relative speed to vehicle 12100) basedon the distance information obtained from the imaging units 12101 to12104, thereby particularly extracting, as a preceding vehicle, athree-dimensional object that is closest on a traveling road of thevehicle 12100 and is traveling at a predetermined speed (for example, 0km/h or more) in substantially the same direction as the vehicle 12100.Furthermore, the microcomputer 12051 can set an inter-vehicular distanceto be secured behind a preceding vehicle in advance to perform automaticbraking control (including following stop control) and automaticacceleration control (including following start control). In thismanner, the collaborative control for the purpose of automatic drivingto autonomously travel independently of driver's operation can beperformed.

For example, the microcomputer 12051 can classify three-dimensionalobject data on three-dimensional objects in to two-wheeled vehicles,standard-sized vehicles, large vehicles, pedestrians, and otherthree-dimensional objects such as telephone poles on the basis ofdistance information obtained from the imaging units 12101 to 12104 andextract the three-dimensional object data, and use the three-dimensionalobject data for automatic obstacle avoidance. For example, themicrocomputer 12051 distinguishes obstacles around the vehicle 12100 toobstacles that can be visually recognized by a driver of the vehicle12100 and obstacles that are difficult to be visually recognized. Themicrocomputer 12051 determines a collision risk indicating the degree ofdanger of collision with each obstacle, and in a situation where acollision risk is equal to or higher than a set value and the vehiclecan possibly collide, the microcomputer 12051 can assist the driving forcollision avoidance by outputting warning to the driver through theaudio speaker 12061 or the display unit 12062 and performing forceddeceleration and avoidance steering through the driving system controlunit 12010.

At least one of the imaging units 12101 to 12104 may be an infraredcamera configured to detect infrared rays. For example, themicrocomputer 12051 can determine whether a pedestrian is present inimages taken by the imaging units 12101 to 12104 to recognize thepedestrian. For example, the pedestrian is recognized by a procedure forextracting feature points in images taken by the imaging units 12101 to12104 as infrared cameras and a procedure for determining whether anobject is a pedestrian by performing pattern matching on a series offeature points indicating the contour of the object. When themicrocomputer 12051 determines that a pedestrian is present in theimages taken by the imaging units 12101 to 12104 and recognizes thepedestrian, the voice and image output unit 12052 controls the displayunit 12062 to display the rectangular contour line for emphasizing therecognized pedestrian in a superimposed manner. The voice and imageoutput unit 12052 may control the display unit 12062 to display an iconindicating a pedestrian at a desired position.

While the embodiments of the present disclosure have been described, thetechnical scope of the present disclosure is not limited to theabove-mentioned embodiments as they are, and can be variously changedwithin the range not departing from the gist of the present disclosure.The components in different embodiments and modifications may becombined as appropriate.

The effects in each embodiment described herein are merely demonstrativeand are not limited, and other effects may be obtained.

The present technology can also employ the following configurations.

(1) A solid-state imaging device, comprising:

a semiconductor substrate including a photoelectric conversion element;

a lens disposed above a first light incident surface of thephotoelectric conversion element; and

a plurality of columnar structures disposed on a surface parallel to thefirst light incident surface that is located between a second lightincident surface of the lens and the first light incident surface of thephotoelectric conversion element, wherein

the columnar structure includes at least one of silicon, germanium,gallium phosphide, aluminum oxide, cerium oxide, hafnium oxide, indiumoxide, tin oxide, niobium pentoxide, magnesium oxide, tantalumpentoxide, titanium pentoxide, titanium oxide, tungsten oxide, yttriumoxide, zinc oxide, zirconia, cerium fluoride, gadolinium fluoride,lanthanum fluoride, and neodymium fluoride.

(2) The solid-state imaging device according to the (1), wherein acrystal state of the columnar structure is a single crystal, apolycrystal, or amorphous.

(3) The solid-state imaging device according to the (1) or (2), whereina refractive index of the columnar structure is 1.5 or more.

(4) The solid-state imaging device according to any one of the (1) to(3), wherein the columnar structures are arranged on the surfaceparallel to the first light incident surface in accordance with squarearrangement, hexagonal close-packed arrangement, or random arrangement.(5) The solid-state imaging device according to any one of the (1) to(4), wherein

a diameter of the columnar structure is 30 nanometers (nm) or more and200 nm or less, and

a pitch between the columnar structures is 200 nanometers (nm) or moreand 1,000 nm or less.

(6) The solid-state imaging device according to any one of the (1) to(5), wherein the columnar structure includes a tapered shape a diameterof which decreases or increases from the surface parallel to the firstlight incident surface toward the second light incident surface of thelens.(7) The solid-state imaging device according to the (6), wherein anelevation angle of a side surface of the columnar structure with respectto the surface parallel to the first light incident surface is 45degrees or more and less than 90 degrees or more than 90 degrees and 135degrees or less.(8) The solid-state imaging device according to any one of the (1) to(5), wherein a diameter of the columnar structure changes step by stepfrom the surface parallel to the first light incident surface toward thesecond light incident surface of the lens.(9) The solid-state imaging device according to any one of the (1) to(8), wherein the columnar structures include two or more kinds ofcolumnar structures having different diameters.(10) The solid-state imaging device according to the (1), furthercomprising a color filter that selectively transmits light having aparticular wavelength, the color filter being disposed between thesecond light incident surface of the lens and the first light incidentsurface of the photoelectric conversion element.(11) The solid-state imaging device according to the (10), wherein thecolumnar structure is disposed inside the color filter.(12) The solid-state imaging device according to any one of the (1) to(10), wherein at least a part of each of the columnar structures isdisposed in a trench extending from a surface of the semiconductorsubstrate on a side opposed to the lens toward the photoelectricconversion element in the semiconductor substrate.(13) The solid-state imaging device according to the (10), furthercomprising a planarization film disposed between the color filter andthe semiconductor substrate, a surface of the planarization film opposedto the color filter being planarized, wherein

the columnar structures are disposed inside the planarization film.

(14) The solid-state imaging device according to the (10), wherein

the semiconductor substrate includes a first photoelectric conversionelement and a second photoelectric conversion element,

the lens includes a first lens disposed above a first light incidentsurface of the first photoelectric conversion element and a second lensdisposed above a first light incident surface of the secondphotoelectric conversion element,

the color filter is disposed between the first photoelectric conversionelement and the first lens, and is not disposed between the secondphotoelectric conversion element and the second lens, and

among the columnar structures,

-   -   a plurality of first columnar structures disposed between the        first light incident surface of the first photoelectric        conversion element and the second light incident surface of the        first lens have spectroscopic characteristics that absorb        infrared light, and    -   a plurality of second columnar structures disposed between the        first light incident surface of the second photoelectric        conversion element and the second light incident surface of the        second lens have spectroscopic characteristics that transmit        infrared light.        (15) The solid-state imaging device according to any one of        the (1) to (13), wherein

the semiconductor substrate includes a first photoelectric conversionelement and a second photoelectric conversion element,

the lens includes a first lens disposed above the first light incidentsurface of the first photoelectric conversion element and a second lensdisposed above the first light incident surface of the secondphotoelectric conversion element, and

of the columnar structures,

-   -   a diameter of each of a plurality of first columnar structures        disposed between the first light incident surface of the first        photoelectric conversion element and the second light incident        surface of the first lens and a diameter of each of a plurality        of second columnar structures disposed between the first light        incident surface of the second photoelectric conversion element        and the second light incident surface of the second lens are        different from each other.        (16) The solid-state imaging device according to the (10) or        (11), wherein

the color filter includes a first color filter that selectivelytransmits light having a first particular wavelength and a second colorfilter that selectively transmits light having the first particularwavelength,

the semiconductor substrate includes a first photoelectric conversionelement and a second photoelectric conversion element,

the lens includes a first lens disposed above the first light incidentsurface of the first photoelectric conversion element and a second lensdisposed above the first light incident surface of the secondphotoelectric conversion element,

the first color filter is disposed between the first photoelectricconversion element and the first lens,

the second color filter is disposed between the second photoelectricconversion element and the second lens, and

of the columnar structures, a diameter of each of a plurality of firstcolumnar structures disposed between the first light incident surface ofthe first photoelectric conversion element and the second light incidentsurface of the first lens and a diameter of each of a plurality ofsecond columnar structures disposed between the first light incidentsurface of the second photoelectric conversion element and the secondlight incident surface of the second lens are different from each other.

(17) The solid-state imaging device according to any one of the (1) to(16), wherein the columnar structures have spectroscopic characteristicsthat selectively transmit any one of light having a wavelength componentof red, light having a wavelength component of green, light having awavelength component of blue, and infrared light.(18) An electronic device, comprising:

a solid-state imaging device;

an optical system that forms an image of incident light on a lightreceiving surface of the solid-state imaging device; and

a control unit that controls the solid-state imaging device, wherein

the solid-state imaging device includes:

-   -   a semiconductor substrate including a photoelectric conversion        element;    -   a lens disposed above a first light incident surface of the        photoelectric conversion element; and    -   a plurality of columnar structures disposed on a surface        parallel to the first light incident surface that is located        between a second light incident surface of the lens and the        first light incident surface of the photoelectric conversion        element, and

the columnar structure includes at least one of silicon, germanium,gallium phosphide, aluminum oxide, cerium oxide, hafnium oxide, indiumoxide, tin oxide, niobium pentoxide, magnesium oxide, tantalumpentoxide, titanium pentoxide, titanium oxide, tungsten oxide, yttriumoxide, zinc oxide, zirconia, cerium fluoride, gadolinium fluoride,lanthanum fluoride, and neodymium fluoride.

(19) A solid-state imaging device, including:

a semiconductor substrate including a plurality of photoelectricconversion elements;

a lens disposed above a first light incident surface of each of thephotoelectric conversion elements;

a plurality of color filters, each disposed between the semiconductorsubstrate and the lens to each of the photoelectric conversion elements,that transmit light having a particular wavelength; and

a plurality of columnar structures disposed on a surface parallel to thefirst light incident surface that is located between a second lightincident surface of the lens and the first light incident surface of thephotoelectric conversion element, in which

the color filters include a first color filter that selectivelytransmits light in a first wavelength region and a second color filterthat selectively transmits light in a second wavelength region differentfrom the first wavelength region, and

among the columnar structures, a plurality of columnar structureslocated between a photoelectric conversion element and a lens anddisposed at positions opposed to each other across the first colorfilter have spectroscopic characteristics that absorb at least light ina wavelength region between the first wavelength region and the secondwavelength region.

(20) A solid-state imaging device, including:

a semiconductor substrate including a plurality of photoelectricconversion elements arranged in a two-dimensional grid pattern;

a lens disposed above a first light incident surface of each of thephotoelectric conversion elements; and

a plurality of columnar structures disposed on a surface parallel to thefirst light incident surface that is located between a second lightincident surface of the lens and the first light incident surface of thephotoelectric conversion element, in which

the columnar structures are provided for the photoelectric conversionelement located at a peripheral position in the two-dimensional gridpattern arrangement.

(21) A solid-state imaging device, including:

a semiconductor substrate including a photoelectric conversion element;

a lens disposed above a first light incident surface of thephotoelectric conversion element; and

a plurality of columnar structures disposed on a surface parallel to thefirst light incident surface that is located between a second lightincident surface of the lens and the first light incident surface of thephotoelectric conversion element, in which

the columnar structures are arranged in two or more rows at positionscorresponding to a peripheral part of the photoelectric conversionelement.

(22) A solid-state imaging device, including:

a semiconductor substrate including an effective pixel region, in whicha plurality of photoelectric conversion elements are arranged in atwo-dimensional grid pattern, and a shielding region located around theeffective pixel region; and

a plurality of columnar structures located in the shielding region andarranged with a pitch shorter than a pitch of the photoelectricconversion elements.

(23) A solid-state imaging device, including:

a semiconductor substrate including a plurality of photoelectricconversion elements arranged in a two-dimensional grid pattern; and

a plurality of columnar structures arranged on a light incident surfaceside of the semiconductor substrate and in two or more rows between thephotoelectric conversion elements.

(24) A solid-state imaging device, including:

a semiconductor substrate including a photoelectric conversion element;

a lens disposed above a light incident surface of the photoelectricconversion element; and

a plurality of columnar structures disposed inside the lens and on asurface parallel to the light incident surface of the photoelectricconversion element.

REFERENCE SIGNS LIST

-   -   1 electronic device    -   10, 10-2 to 10-28 solid-state imaging device (CMOS image sensor)    -   11 pixel array    -   12 row driver    -   13 column processing circuit    -   14 column driver    -   15 system controller    -   18 signal processor    -   19 data storage    -   20 imaging lens    -   30 storage    -   50 processor    -   50, 50B, 50B11 to 50B14, 50B21 to 50B24, 50B31 to 50B34, 50G,        50G1, 50G2, 50G11 to 50G18, 50G21 to 50G28, 50G31 to 50G38,        50IR, 50R, 50R11 to 50R14, 50R21 to 50R24, 50R31 to 50R34 unit        pixel    -   51 transfer transistor    -   52 reset transistor    -   53 amplifier transistor    -   54 selection transistor    -   60, 860 color filter array    -   61, 861, 1261, 1262 unit pattern    -   71 photoreceiver chip    -   72 circuitry chip    -   100 semiconductor substrate    -   101 N-type semiconductor region    -   102 P-type semiconductor region    -   103, 105 insulator film    -   104 anti-reflection film    -   106 shielding film    -   107, 107B, 107G, 1071R, 107R color filter    -   108, 1918, 2108, 2118, 2508B, 2508G, 2508R, 2608, 2708 on-chip        lens    -   109, 2109 passivation film    -   110, 110B, 110G, 110R, 211, 212, 310, 410, 610, 810B, 810G,        810R, 910B, 910R, 1010G, 1010GB, 1010GR, 1210B, 1210R, 1310B,        1310R, 1410B, 1410G, 1410R, 1510, 1610B, 1610G, 1610R, 1910,        2010G, 2010R, 2110, 2510A, 2510B, 2510G, 2510R, 2610 pillar    -   110A, 2508A material film    -   501 planarization film    -   700B, 700G, 700R, 800B, 800G, 800R, 900B, 900R, 1000G, 1400B,        1400G, 1400R, 1500, 1900, 2100 pillar array    -   1201, 1901, 2101 effective pixel region    -   1202 center region    -   1203 peripheral region    -   1304 intermediate region    -   1902, 2102 shielding region    -   1916, 2116 OPB solid film    -   2126 anti-flare film    -   L10, L11, L12 light    -   LD pixel driving line    -   LD51 transfer transistor driving line    -   LD52 reset transistor driving line    -   LD54 selection transistor driving line    -   PD photodiode    -   R1, R25 resist film    -   VSL vertical signal line

The invention claimed is:
 1. A solid-state imaging device, comprising: aplurality of pixels, wherein each pixel of the plurality of pixelscomprises: a semiconductor substrate that includes a photoelectricconversion element; a lens above a first light incident surface of thephotoelectric conversion element; a color filter between a second lightincident surface of the lens and the first light incident surface of thephotoelectric conversion element, wherein the color filter is configuredto selectively transmit light having a particular wavelength; and aplurality of columnar structures on a surface parallel to the firstlight incident surface, wherein the plurality of columnar structures isbetween the second light incident surface of the lens and the firstlight incident surface of the photoelectric conversion element, theplurality of columnar structures corresponding to a first pixel of theplurality of pixels has spectroscopic characteristics and is configuredto absorb infrared light, and the plurality of columnar structuresincludes at least one of silicon, germanium, gallium phosphide, aluminumoxide, cerium oxide, hafnium oxide, indium oxide, tin oxide, niobiumpentoxide, magnesium oxide, tantalum pentoxide, titanium pentoxide,titanium oxide, tungsten oxide, yttrium oxide, zinc oxide, zirconia,cerium fluoride, gadolinium fluoride, lanthanum fluoride, and neodymiumfluoride, and the color filter is not disposed in at least one pixel ofthe plurality of pixels, wherein the at least one pixel is differentfrom the first pixel, the at least one pixel corresponds to a pixelconfigured to selectively transmit the infrared light, and the pluralityof columnar structures in the at least one pixel has spectralcharacteristics and is configured to transmit the infrared light.
 2. Thesolid-state imaging device according to claim 1, wherein a crystal stateof each of the plurality of columnar structures is one of a singlecrystal, a polycrystal, or amorphous.
 3. The solid-state imaging deviceaccording to claim 1, wherein a refractive index of the plurality ofcolumnar structures is 1.5 or more.
 4. The solid-state imaging deviceaccording to claim 1, wherein each of the plurality of columnarstructures is on the surface parallel to the first light incidentsurface and has one of a square arrangement, a hexagonal close-packedarrangement, or a random arrangement.
 5. The solid-state imaging deviceaccording to claim 1, wherein a diameter of each of the plurality ofcolumnar structures ranges from 30 nanometers (nm) to 200 nm, and apitch between each of the plurality of columnar structures ranges from200 nm to 1,000 nm.
 6. The solid-state imaging device according to claim1, wherein each of the plurality of columnar structures includes atapered shape with a diameter that decreases or increases from thesurface parallel to the first light incident surface toward the secondlight incident surface of the lens.
 7. The solid-state imaging deviceaccording to claim 6, wherein an elevation angle of a side surface ofeach of the plurality of columnar structures with respect to the surfaceparallel to the first light incident surface ranges from 45 degrees toless than 90 degrees, or the elevation angle ranges from more than 90degrees to 135 degrees.
 8. The solid-state imaging device according toclaim 1, wherein a diameter of each of the plurality of columnarstructures changes step by step from the surface parallel to the firstlight incident surface towards the second light incident surface of thelens.
 9. The solid-state imaging device according to claim 1, whereinthe plurality of columnar structures includes at least two kinds ofcolumnar structures having different diameters.
 10. The solid-stateimaging device according to claim 1, wherein the plurality of columnarstructures is inside the color filter.
 11. The solid-state imagingdevice according to claim 1, wherein at least a part of the plurality ofcolumnar structures is in a trench that extends from a surface of thesemiconductor substrate towards the photoelectric conversion element inthe semiconductor substrate, and the surface of the semiconductorsubstrate is on a side opposite to the lens.
 12. The solid-state imagingdevice according to claim 1, further comprising a planarization filmbetween the color filter and the semiconductor substrate, wherein asurface of the planarization film opposite to the color filter isplanarized, and the plurality of columnar structures are inside theplanarization film.
 13. The solid-state imaging device according toclaim 1, wherein each of the plurality of columnar structurescorresponding to the first pixel of the plurality of pixels has adiameter different from each of the plurality of columnar structurescorresponding to a second pixel of the plurality of pixels.
 14. Thesolid-state imaging device according to claim 1, wherein the colorfilter corresponding to the first pixel of the plurality of pixels isconfigured to selectively transmit light having a first particularwavelength, the color filter corresponding to a second pixel of theplurality of pixels is configured to selectively transmit light having asecond particular wavelength, and each of the plurality of columnarstructures corresponding to the first pixel has a diameter differentfrom each of the plurality of columnar structures corresponding to thesecond pixel.
 15. The solid-state imaging device according to claim 1,wherein the plurality of columnar structures has spectroscopiccharacteristics to selectively transmit one of light having a wavelengthcomponent of red, light having a wavelength component of green, lighthaving a wavelength component of blue, or the infrared light.
 16. Anelectronic device, comprising: a solid-state imaging device; an opticalsystem configured to form an image corresponding to light incident on alight receiving surface of the solid-state imaging device; and a controlunit configured to control the solid-state imaging device, wherein thesolid-state imaging device includes a plurality of pixels, wherein eachpixel of the plurality of pixels comprises: a semiconductor substratethat includes a photoelectric conversion element; a lens above a firstlight incident surface of the photoelectric conversion element; a colorfilter between a second light incident surface of the lens and the firstlight incident surface of the photoelectric conversion element, whereinthe color filter is configured to selectively transmit the light havinga particular wavelength; and a plurality of columnar structures on asurface parallel to the first light incident surface, wherein  theplurality of columnar structures is between the second light incidentsurface of the lens and the first light incident surface of thephotoelectric conversion element,  the plurality of columnar structurescorresponding to a first pixel of the plurality of pixels hasspectroscopic characteristics and is configured to absorb infraredlight, and  the plurality of columnar structures includes at least oneof silicon, germanium, gallium phosphide, aluminum oxide, cerium oxide,hafnium oxide, indium oxide, tin oxide, niobium pentoxide, magnesiumoxide, tantalum pentoxide, titanium pentoxide, titanium oxide, tungstenoxide, yttrium oxide, zinc oxide, zirconia, cerium fluoride, gadoliniumfluoride, lanthanum fluoride, and neodymium fluoride, and the colorfilter is not disposed in at least one pixel of the plurality of pixels,wherein the at least one pixel is different from the first pixel, the atleast one pixel corresponds to a pixel configured to selectivelytransmit the infrared light, and the plurality of columnar structures inthe at least one pixel has spectral characteristics and is configured totransmit the infrared light.